fix(auth): strip trailing slashes from OAuth metadata URLs #3459

Job	Run time
checks / docs	32s
checks / readme-snippets	11s
checks / pre-commit	53s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 2s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.10, locked, ubuntu-latest)	1m 6s
checks / test (3.10, locked, windows-latest)	2m 8s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 4s
checks / test (3.11, locked, windows-latest)	2m 24s
checks / test (3.13, locked, ubuntu-latest)	1m 2s
checks / test (3.14, locked, windows-latest)	1m 52s
checks / test (3.11, lowest-direct, windows-latest)	1m 52s
checks / test (3.11, locked, ubuntu-latest)	1m 7s
checks / test (3.12, locked, windows-latest)	1m 48s
checks / test (3.13, lowest-direct, windows-latest)	1m 50s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 2s
checks / test (3.14, lowest-direct, windows-latest)	1m 37s
checks / test (3.12, locked, ubuntu-latest)	1m 30s
checks / test (3.14, locked, ubuntu-latest)	1m 8s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 12s
checks / test (3.10, lowest-direct, windows-latest)	1m 52s
checks / test (3.12, lowest-direct, windows-latest)	1m 56s
checks / test (3.13, locked, windows-latest)	1m 49s
all-green	2s
	31m 59s

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