telemetry(chat): differentiate chat vs agenticChat

[chungjac]

Problem

• differentiate Chat vs AgenticChat for cwsprChatConversationType
• stop button functionality changed so event is being incorrectly emitted

Solution

• emit AgenticChat for cwsprChatConversationType
• correctly emit event when user clicks stop button
• telemetry(amazonq): AgenticChat cwsprChatConversationType aws-toolkit-common#1012

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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.