fix: mls group creation recovery [WPB-27337]

[Garzas]

https://wearezeta.atlassian.net/browse/WPB-27337

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• The PR Title

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What's new in this PR?

Issues

When MLS group establishment fails after the backend conversation has already been created, Android displays a generic error. Starting the creation flow again can create a duplicate conversation.

Causes

Android did not retain the pending conversation ID and treated the MLS establishment failure like a complete conversation creation failure.

Solutions

• Keep the pending conversation ID after an MLS establishment failure.
• Show a dedicated dialog explaining that the conversation is not ready yet.
• Allow the user to retry using the existing conversation instead of creating another one.
• Allow the user to close the flow while recovery continues through Kalium.
• Retry MLS establishment when the user opens a visible PENDING_CREATION conversation.
• Prevent repeated retries within the same conversation ViewModel instance.
• Add automated tests for the dialog state, manual retry and retry after opening a pending conversation.

[codecov]

Codecov Report

❌ Patch coverage is 90.90909% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 52.27%. Comparing base (10f530d) to head (5e6c380).

Files with missing lines	Patch %	Lines
...i/home/newconversation/NewConversationViewModel.kt	91.11%	1 Missing and 3 partials ⚠️
...me/conversations/info/ConversationInfoViewModel.kt	90.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #5191      +/-   ##
===========================================
+ Coverage    52.19%   52.27%   +0.07%     
===========================================
  Files          668      668              
  Lines        23972    24021      +49     
  Branches      3950     3960      +10     
===========================================
+ Hits         12512    12556      +44     
- Misses       10300    10301       +1     
- Partials      1160     1164       +4     

Files with missing lines	Coverage Δ
...me/conversations/info/ConversationInfoViewModel.kt	81.31% <90.00%> (+1.07%)	⬆️
...i/home/newconversation/NewConversationViewModel.kt	72.59% <91.11%> (+3.95%)	⬆️

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[github-actions]

Test Results

2 271 tests   2 271 ✅  2m 31s ⏱️
  250 suites      0 💤
  250 files        0 ❌

Results for commit 5e6c380.