[python] support shiny apps if ext not installed #909

Job	Run time
Lint	1m 49s
Python Tests (ubuntu-latest, 3.8)	2m 11s
Check Python types	7m 13s
Test Positron IPyKernel (ubuntu-latest, 3.8)	2m 58s
Python Tests (ubuntu-latest, 3.12)	2m 19s
Test Minimum Positron IPyKernel Dependencies (ubuntu-latest, 3.8)	3m 35s
Test Positron IPyKernel (macos-13, 3.9)	3m 8s
Test Positron IPyKernel (windows-latest, 3.10)	7m 29s
Test TypeScript (ubuntu-latest, 3.x, ts-unit)	4m 6s
Test Positron IPyKernel (ubuntu-latest, 3.11)	2m 59s
Test TypeScript (ubuntu-latest, 3.x, functional)	2m 50s
Test Positron IPyKernel (ubuntu-latest, 3.12)	1m 38s
Test TypeScript (macos-12, 3.x, ts-unit)	5m 40s
Test TypeScript (macos-12, 3.x, venv)	8m 10s
Test TypeScript (macos-12, 3.x, single-workspace)	7m 44s
Test TypeScript (macos-12, 3.x, debugger)	5m 52s
Test TypeScript (macos-12, 3.x, functional)	5m 32s
Test TypeScript (macos-12, 3.x, smoke)	11m 5s
Test TypeScript (windows-latest, 3.x, ts-unit)	12m 8s
Test TypeScript (windows-latest, 3.x, functional)	6m 47s
	1h 45m 13s

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