[heft] Add support for mapping TS Error codes to warnings in the `typescript.json` config file.

[iclanton]

Summary

As mentioned in this issue (https://github.com/microsoft/rushstack/issues/3522), it would be useful to have this feature implemented: https://github.com/microsoft/rushstack/blob/main/apps/heft/src/plugins/TypeScriptPlugin/TypeScriptBuilder.ts#L780

Repro steps

N/A

Details

https://github.com/microsoft/rushstack/blob/main/apps/heft/src/plugins/TypeScriptPlugin/TypeScriptBuilder.ts#L780

Standard questions

Please answer these questions to help us investigate your issue more quickly:

Question	Answer
@rushstack/heft version?	Current
Operating system?	Any
Would you consider contributing a PR?	Yes
Node.js version (node -v)?	Any

[octogonz]

+1 I'm surprised the compiler itself doesn't provide this feature

[Faithfinder]

I've read somewhere that TS error codes aren't considered "stable". Found this comment right now: https://github.com/microsoft/TypeScript/issues/22011#issuecomment-384815956 but I think I saw a more elaborate one somewhere