Refactor and centralize file mimeType integrity check and sanitization (#20889)

# Introduction
closes https://github.com/twentyhq/private-issues/issues/484

This PR refactors the writeFile API to never expect to be passed a
mimetype, its extract is done programmatically low level so any callers
will pass through
Same for the file sanitization

## IANA override
Disclaimer for consistency we existing behavior we wanted to always have
`application/typescript`
- should we rather consider fallbacking to octect-steam instead ?
- Any pulbic assets that has .ts will now also fallback to
`application/typescript` instead of the official IANA

## Integration
Added coverage

packages/twenty-server/src/engine/core-modules/sdk-client/sdk-client-generation.service.ts

@@ -157,7 +157,6 @@ export class SdkClientGenerationService {
         fileFolder: FileFolder.GeneratedSdkClient,
         resourcePath: SDK_CLIENT_ARCHIVE_NAME,
         sourceFile: archiveBuffer,
-        mimeType: 'application/zip',
         settings: { isTemporaryFile: false, toDelete: false },
       });