PosgreSQL: precision in column with type 'geography' generates duplicates migration

[MrRedBobr]

Issue Description

"Precision" for the geography column duplicates the migration.

Steps to Reproduce

1. Create geography column.

   @Column({
     type: 'geography',
     nullable: true,
     spatialFeatureType: 'Point',
     srid: 4326,
     transformer: {
       from(point: GeographyPoint): LocationDto {
         if (point) {
           const [lat, lng] = point.coordinates;
           return { lat, lng };
         } else {
           return null;
         }
       },
       to(location: LocationDto): GeographyPoint {
         return location
           ? {
               type: 'Point',
               coordinates: [location.lat, location.lng],
             }
           : null;
       },
     },
   })
   location?: LocationInput;

2. Generate migration and run it.

3. Change precision for this column.

   @Column({
     type: 'geography',
     nullable: true,
     spatialFeatureType: 'Point',
     srid: 4326,
     precision: 20, // add
     transformer: {
       from(point: GeographyPoint): LocationDto {
         if (point) {
           const [lat, lng] = point.coordinates;
           return { lat, lng };
         } else {
           return null;
         }
       },
       to(location: LocationDto): GeographyPoint {
         return location
           ? {
               type: 'Point',
               coordinates: [location.lat, location.lng],
             }
           : null;
       },
     },
   })
   location?: LocationInput;

export class dev1654518273416 implements MigrationInterface {
    name = 'dev1654518273416'

    public async up(queryRunner: QueryRunner): Promise<void> {
        await queryRunner.query(`ALTER TABLE "any_table_name" ALTER COLUMN "location" TYPE geography(Point,4326)`);
    }

    public async down(queryRunner: QueryRunner): Promise<void> {
        await queryRunner.query(`ALTER TABLE "any_table_name" ALTER COLUMN "location" TYPE geography(Point,4326)`);
    }

}

3. Run this migration
4. Run migration:generate one more time

5. In the new migration we can see duplicate

   
   export class dev1654518876605 implements MigrationInterface {
   name = 'dev1654518876605'
   
   public async up(queryRunner: QueryRunner): Promise<void> {
       await queryRunner.query(`ALTER TABLE "any_table_name" ALTER COLUMN "location" TYPE geography(Point,4326)`);
   }
   
   public async down(queryRunner: QueryRunner): Promise<void> {
       await queryRunner.query(`ALTER TABLE "any_table_name" ALTER COLUMN "location" TYPE geography(Point,4326)`);
   }

}

### My Environment

<!--
  Please add any other relevant dependencies to this table at the end.
  For example: Electron, React Native, or NestJS.
-->

| Dependency          | Version  |
| ---                 | ---      |
| Operating System    |  windows        |
| Node.js version     | v16.13.2  | <!-- run `node -v` to obtain this -->
| Typescript version  | 4.4.4  | <!-- run `npm list typescript` to obtain this -->
| TypeORM version     | 0.2.41  | <!-- run `npm list typeorm` to obtain this -->
| NestJS     | 8.1.2  | 

### Additional Context

Precision added in https://github.com/typeorm/typeorm/pull/7166

### Relevant Database Driver(s)

<!-- Put "yes" instead of "no" to your issue's relevant databases -->

| DB Type           | Reproducible  |
|-------------------| ---           |
| `aurora-mysql`    | no            |
| `aurora-postgres` | no            |
| `better-sqlite3`  | no            |
| `cockroachdb`     | no            |
| `cordova`         | no            |
| `expo`            | no            |
| `mongodb`         | no            |
| `mysql`           | no            |
| `nativescript`    | no            |
| `oracle`          | no            |
| `postgres`        | yes            |
| `react-native`    | no            |
| `sap`             | no            |
| `spanner`         | no            |
| `sqlite`          | no            |
| `sqlite-abstract` | no            |
| `sqljs`           | no            |
| `sqlserver`       | no            |

### Are you willing to resolve this issue by submitting a Pull Request?

<!-- Put "✅" (:white_check_mark:) to one of these options, left "✖️" (:heavy_multiplication_x:) others: -->

 - ✖️ Yes, I have the time, and I know how to start.
 - ✖️ Yes, I have the time, but I don't know how to start. I would need guidance.
 - ✖️ No, I don’t have the time, but I can support (using donations) development.
 - ✅ No, I don’t have the time and I’m okay to wait for the community / maintainers to resolve this issue.

<!--
  Remember that first-time contributors are welcome! 🙌
  👋 Have a great day and thank you for the bug report!
-->

[MrRedBobr]

For now it can be fixed with process variable:

@Column({
      type: 'geography',
      nullable: true,
      spatialFeatureType: 'Point',
      srid: 4326,
     ...(!process?.env?.TYPEORM_GENERATE && { precision: 15 }), //pay attantion
      transformer: {
        from(point: GeographyPoint): LocationDto {
          if (point) {
            const [lat, lng] = point.coordinates;
            return { lat, lng };
          } else {
            return null;
          }
        },
        to(location: LocationDto): GeographyPoint {
          return location
            ? {
                type: 'Point',
                coordinates: [location.lat, location.lng],
              }
            : null;
        },
      },
    })
  location?: LocationInput;

Paist this string in ormconfig.js:

process.env.TYPEORM_GENERATE = true;