[transactionSchema] Use constants for integral values & add missing `length` check for `signatures`

Description

This schema uses constants for minLength, maxLength

"module": {
  "dataType": "string",
  "minLength": MIN_MODULE_NAME_LENGTH,
  "maxLength": MAX_MODULE_NAME_LENGTH,
  "fieldNumber": 1
},
"command": {
  "dataType": "string",
  "minLength": MIN_COMMAND_NAME_LENGTH,
  "maxLength": MAX_COMMAND_NAME_LENGTH,
  "fieldNumber": 2
},

But in code, these are added as hard coded values

dataType: 'string',
fieldNumber: 1,
minLength: 1, // ***
maxLength: 32, // ***
},
command: {
dataType: 'string',
fieldNumber: 2,
minLength: 1, // ***
maxLength: 32, // ***
},

So they need to be replaced with constants per above schema.

Although length check is missing in signatures property (in code) for the reason: "it is to support unsigned tx as well where there is no signature". Thus we can just add this comment in schema, so we know why it's not added there.

"signatures": {
      "dataType": "array",
      "items": {
          "dataType": "bytes",
          "length": ED25519_SIGNATURE_LENGTH // ***
      },
      "fieldNumber": 7
  }

Motivation

If tomorrow we need to change lengths for module/command names, it would have a global effect by changing one line.

LiskArchive / lisk-sdk

[transactionSchema] Use constants for integral values & add missing `length` check for `signatures` #8766

Description

Motivation

Additional Information