python/ci: adjust CI testing for python 3.8 #1177

Job	Run time
Lint	1m 38s
Check Python types	3m 9s
Test Positron IPyKernel (macos-latest, 3.9)	1m 54s
Python Tests (ubuntu-latest, 3.8)	1m 45s
Test Positron IPyKernel (windows-latest, 3.10)	7m 25s
Python Tests (ubuntu-latest, 3.12)	1m 42s
Test Positron IPyKernel (ubuntu-latest, 3.11)	2m 52s
Test Positron IPyKernel (ubuntu-latest, 3.12)	2m 54s
Test Minimum Positron IPyKernel Dependencies (ubuntu-latest, 3.8)	4m 10s
Test TypeScript (ubuntu-latest, 3.x, ts-unit)	3m 0s
Test TypeScript (ubuntu-latest, 3.x, functional)	2m 0s
Test TypeScript (macos-latest, 3.x, ts-unit)	2m 39s
Test TypeScript (macos-latest, 3.x, venv)	3m 0s
Test TypeScript (macos-latest, 3.x, single-workspace)	2m 41s
Test TypeScript (macos-latest, 3.x, debugger)	2m 50s
Test TypeScript (macos-latest, 3.x, functional)	1m 37s
Test TypeScript (macos-latest, 3.x, smoke)	3m 25s
Test TypeScript (windows-latest, 3.x, ts-unit)	7m 33s
Test TypeScript (windows-latest, 3.x, functional)	6m 8s
	1h 2m 22s

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