fix(chat): agentic chat working stop

[ashishrp-aws]

Problem

Conversation needs stop button to stop the agentic chat loop and conversations topping for new user prompt.

Solution

• Enables prompt when chat loop is running for new user prompt.
• Fixes chat history for stop/user prompts and followup prompts.

---

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[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
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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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[jguoamz]

can you please explain what this do?

[ashishrp-aws]

In some scenarios we are breaking the breaking the assistant response and that empty message is being pushed to chat history as assistant response. so in that specific case, we are correcting the history by clearing up the recent messages. Also making sure that to not toolUse messages with empty content