fix(mls): set correct CipherSuite when establishing new created group

[mchenani]

---

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

---

What's new in this PR?

Update CipherSuite in DB after conversation is established.

---

PR Post Submission Checklist for internal contributors (Optional)

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

---

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.

---

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]

Test Results

2 865 tests   2 742 ✔️  22s ⏱️
   491 suites     123 💤
   491 files           0 ❌

Results for commit 3815444.

♻️ This comment has been updated with latest results.

[datadog-wireapp]

Datadog Report

Branch report: fix/set-correct-cs-to-new-groups
Commit report: d5ba8d8
Test service: kalium-jvm

✅ 0 Failed, 2883 Passed, 107 Skipped, 7.22s Total Time