Ignore the `{"special": "deep"}` default value introduced by Joi when invoking the `default()` function without arguments.

[cmaster11]

Ignore the {"special": "deep"} default value introduced by Joi when invoking the default() function without arguments.

Ref: https://github.com/hapijs/joi/blob/e7e9c5d18dafaa510a7ece02c225653db5fc998f/lib/manifest.js#L179

Without this fix, the generated TS code would look like:

export interface Test {"special":"deep"} | {
  num: 1 | number;
  str: "Test" | string;
  strWithSpecialChars: "Test\\World$Hello🚀Hey\nYay" | string;
}

Note: there is an edge case here where if someone were to use the {"special":"deep"} values as default, this would not be printed in the generated type default. I think it's an acceptable "bug" because the Joi library dumps this value in the result of the describe function without providing additional information.

---

Also, fix the generated types in case we have objects with default values, where we then need to use export type = instead of export interface because the latter one is invalid with a union.

So, instead of the invalid

export interface Test {"something":"deep"} | {
  something?: string;
}

we get the proper

export type Test = {"something":"deep"} | {
  something?: string;
}

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.48%. Comparing base (9eb921f) to head (2cb6f45). Report is 20 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #433 +/- ## ========================================== + Coverage 98.46% 98.48% +0.02% ========================================== Files 9 9 Lines 650 661 +11 Branches 251 266 +15 ========================================== + Hits 640 651 +11 Misses 10 10 ```

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[cmaster11]

Ping @mrjono1? :D