Support client_credentials flow with JWT and Basic auth #3591

Job	Run time
checks / pre-commit	32s
checks / readme-snippets	12s
checks / test (3.10, lowest-direct, windows-latest)	1m 57s
checks / test (3.10, highest, ubuntu-latest)	46s
checks / test (3.10, lowest-direct, ubuntu-latest)	40s
checks / test (3.13, lowest-direct, ubuntu-latest)	41s
checks / test (3.11, highest, windows-latest)	2m 10s
checks / test (3.10, highest, windows-latest)	2m 4s
checks / test (3.12, highest, ubuntu-latest)	44s
checks / test (3.11, lowest-direct, ubuntu-latest)	44s
checks / test (3.12, lowest-direct, windows-latest)	2m 50s
checks / test (3.11, lowest-direct, windows-latest)	2m 5s
checks / test (3.12, highest, windows-latest)	3m 0s
checks / test (3.12, lowest-direct, ubuntu-latest)	49s
checks / test (3.11, highest, ubuntu-latest)	45s
checks / test (3.13, highest, windows-latest)	2m 3s
checks / test (3.13, lowest-direct, windows-latest)	2m 18s
checks / test (3.13, highest, ubuntu-latest)	45s
	25m 5s

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