fix(amazonq): Address multiple history bugs

[tsmithsz]

Problem

• fixHistory only processes the first conversation associated with the tab, but there can be multiple. Results in an incomplete history and messes up the history sent in the request
• We currently delete the entire history for a tab if an exception is thrown. This is not ideal and leads to customer confusion when they are not able to continue using their chat history after an error.
• Right-click actions like Explain this code fail when preceding message history contains toolResults. Mynah does not recognize this enum
• Fake messages for tooluse failures are being stored the chat history.

Solution

• Collect message across all conversation associated with the current tab and consolidate them into a single conversation
• Remove clearTab() call when exception is thrown
• Do not include history for requests to Mynah
• Remove clearRecentHistory as this is no longer used
• Do not store these fake messages to the chatHistory

Testing

• Manually tested fixes:
  • Chat history still remains after exception is thrown
  • Mynah no longer throws exception for right-click action following tool execution
    

---

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[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
  • Confirm whether tests should be added or ensure the PR description explains why tests are not required.
• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
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  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.

[ashishrp-aws]

/retryBuilds