feat: handle out of order MLS messages

[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?

I'm re-opening #1958 because it seems to have gotten lost in a rebase.

After reviewing it again I've changed my approach.

1. Handle out order buffered messages when decrypting a message.2
2. Ignore CC's buffered messages when merging commits, because it's much easier and nicer to avoid out order message by enforcing the order of operations in Kalium.

Testing

Test Coveragex

• I have added automated test to this contribution

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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

   434 files  ±0     434 suites  ±0   2m 51s ⏱️ +13s
2 360 tests +2  2 257 ✔️ +2  103 💤 ±0  0 ❌ ±0 

Results for commit 5489d77. ± Comparison against base commit 38df69b.

♻️ This comment has been updated with latest results.

[datadog-wireapp]

Datadog Report

All test runs 4d6d87b 🔗

✅ 2 Total Test Services: 0 Failed, 0 with New Flaky, 2 Passed

Test Services

Service Name	Failed	Known Flaky	New Flaky	Passed	Skipped	Wall Time	Branch View
kalium-ios	0	0	0	1645	56	7m 38s	Link
kalium-jvm	0	0	0	2257	103	13m 51s	Link