Bugfix: Fix quart threadedrunner stop graceful shutdown #1537

Job	Run time
Build Dash Package	3m 5s
Build on Windows	6m 10s
Detect Relevant Path Changes	6s
Run Backend Callback Tests (Python 3.9)	3m 20s
Lint & Unit Tests (Python 3.12)	4m 3s
Lint & Unit Tests (Python 3.8)	3m 32s
Main Dash Tests (Python 3.12, Group 3)	6m 31s
Main Dash Tests (Python 3.8, Group 3)	6m 32s
Main Dash Tests (Python 3.12, Group 2)	8m 39s
Typing Tests	3m 42s
Main Dash Tests (Python 3.12, Group 1)	7m 3s
Main Dash Tests (Python 3.8, Group 2)	9m 51s
Main Dash Tests (Python 3.8, Group 1)	6m 41s
Run Backend Callback Tests (Python 3.12)	3m 16s
WebSocket Tests (Python ${{ matrix.python-version }})	0s
Table Unit/Lint Tests (Python ${{ matrix.python-version }})	0s
DCC Lint Tests (Python ${{ matrix.python-version }})	0s
Table Server Tests (Group ${{ matrix.test-group }})	0s
HTML Components Tests (Python ${{ matrix.python-version }})	0s
DCC Integration Tests (Python ${{ matrix.python-version }}, Group ${{ matrix.test-group }})	0s
Run Background & Async Callback Tests (Python ${{ matrix.python-version }})	0s
Dash Table Visual Tests	0s
Finalize Percy Snapshots	3s
Consolidated Test Report	6s
Store Build Artifacts	-1s
	1h 12m 39s

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