fix(service/microsoft): remove the explicitly specified content-length

[yin1999]

Fixes: #510

I believe that the http client of Zotero would set the correct content-length header. And this is a forbidden header, which means that the programmer should not explicitly set this (the user agent would set this correctly).

For the issue mentioned in #510, it could not translate from Chinese to English. And the status code returned is 400. So this might be due to setting of wrong Content-Length and zotero does not implicitly reject the setting. For unicode other than ascii, the string length is not equal to the content-length. Which has made this error.

Resolving this by removing Content-Length header.

Documentation: https://learn.microsoft.com/en-us/azure/ai-services/translator/reference/v3-0-reference

Tested this locally:

[github-actions]

🚀 This ticket has been resolved in v1.1.0-beta.50. See Release v1.1.0-beta.50 for release notes.