Document `redirect_uri` wire-format change in OAuth migration note #2852

Job	Run time
checks / readme-snippets	11s
checks / pre-commit	45s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 21s
checks / test (3.10, lowest-direct, windows-latest)	1m 34s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 35s
checks / test (3.11, locked, windows-latest)	1m 35s
checks / test (3.14, locked, windows-latest)	2m 42s
checks / test (3.13, locked, ubuntu-latest)	58s
checks / test (3.13, lowest-direct, windows-latest)	1m 56s
checks / test (3.10, locked, windows-latest)	1m 17s
checks / test (3.12, locked, ubuntu-latest)	1m 8s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 38s
checks / test (3.12, lowest-direct, windows-latest)	1m 50s
checks / test (3.12, locked, windows-latest)	1m 44s
checks / test (3.13, locked, windows-latest)	1m 21s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 22s
checks / test (3.14, locked, ubuntu-latest)	2m 6s
checks / test (3.14, lowest-direct, windows-latest)	1m 53s
checks / test (3.11, lowest-direct, windows-latest)	1m 51s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 27s
checks / test (3.10, locked, ubuntu-latest)	1m 2s
checks / test (3.11, locked, ubuntu-latest)	59s
all-green	2s
	32m 17s

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