Gate the test matrix and retry setup-uv's flaky manifest fetch #3428

Job	Run time
checks / pre-commit	1m 4s
checks / readme-snippets	12s
checks / docs	53s
checks / test (3.11, lowest-direct, windows-latest)	1m 57s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 18s
checks / test (3.10, locked, ubuntu-latest)	1m 23s
checks / test (3.10, lowest-direct, windows-latest)	1m 56s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 18s
checks / test (3.10, locked, windows-latest)	2m 3s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 17s
checks / test (3.14, locked, ubuntu-latest)	2m 22s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 14s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 23s
checks / test (3.13, locked, windows-latest)	1m 49s
checks / test (3.11, locked, ubuntu-latest)	1m 27s
checks / test (3.12, locked, windows-latest)	1m 57s
checks / test (3.13, lowest-direct, windows-latest)	1m 59s
checks / test (3.12, lowest-direct, windows-latest)	1m 54s
checks / test (3.14, locked, windows-latest)	2m 45s
checks / test (3.13, locked, ubuntu-latest)	1m 21s
checks / test (3.12, locked, ubuntu-latest)	1m 39s
checks / test (3.14, lowest-direct, windows-latest)	1m 45s
checks / test (3.11, locked, windows-latest)	2m 3s
all-green	3s
	37m 2s

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