* feat: implement async workspace deletion with active session checks
- Updated the DELETE /workspaces/:id endpoint to return 202 Accepted, indicating that the deletion request is processed in the background.
- Added a check for active sessions before allowing workspace deletion, raising a ConflictException if any exist.
- Updated related tests to ensure proper handling of active sessions during workspace deletion.
* fix: Address review issues
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Co-authored-by: Vineeth Voruganti <13438633+VVoruganti@users.noreply.github.com>