fix(amazonq): add message after accept/reject action

[chungjac]

Problem

• Should show a completed message after user completes accept/reject process (just like JB)
• This message does not currently show in VSC

Solution

• Show completed message after user completes accept/reject process

Screen.Recording.2025-01-14.at.2.26.29.PM.mov

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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.