fix: remove content-type hack

[typfel]

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PR Submission Checklist for internal contributors

• The PR Title

  • conforms to the style of semantic commits messages¹ supported in Wire's Github Workflow²
  • contains a reference JIRA issue number like SQPIT-764
  • answers the question: If merged, this PR will: ... ³

• The PR Description

  • is free of optional paragraphs and you have filled the relevant parts to the best of your ability

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What's new in this PR?

Issues

We are sending our messages as protobuf and the server requires the content type to be set to application/x-protobuf. Ktor however doesn't respect overriding the content-type on a request and will always send binary data as application/octet-stream.

We hacked around this on the Android/JVM by installing a http interceptor which re-writes the content type. This has some drawbacks:

1. It only fixes the problem on Android,
2. The moment we need to send another binary content type the hack doesn't work anymore.

And that moment is now because I need to send binary data with content type message/mls when I send MLS messages.

Solutions

Install the ContentNegotiation plugin which can be used to serialise/deserialise requests based on the content-type. We'll only use it to register our missing binary content-types with a dummy converter which simply passes the binary data through as is.

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PR Post Submission Checklist for internal contributors (Optional)

• Wire's Github Workflow has automatically linked the PR to a JIRA issue

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PR Post Merge Checklist for internal contributors

• If any soft of configuration variable was introduced by this PR, it has been added to the relevant documents and the CI jobs have been updated.

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References

1. https://sparkbox.com/foundry/semantic_commit_messages
2. https://github.com/wireapp/.github#usage
3. E.g. feat(conversation-list): Sort conversations by most emojis in the title #SQPIT-764.

[github-actions]

Unit Test Results

  61 files    61 suites   25s ⏱️
293 tests 286 ✔️ 7 💤 0 ❌

Results for commit 2ae36d3.

♻️ This comment has been updated with latest results.

[vitorhugods]

A lot of people would like this one:
ktorio/ktor#1127