Slim ServerMiddleware to `(ctx, call_next)` and add `OpenTelemetryMiddleware` #2910

Job	Run time
checks / pre-commit	42s
checks / readme-snippets	16s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 4s
checks / test (3.11, locked, ubuntu-latest)	58s
checks / test (3.12, lowest-direct, windows-latest)	1m 31s
checks / test (3.10, lowest-direct, windows-latest)	1m 21s
checks / test (3.12, locked, windows-latest)	1m 30s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 10s
checks / test (3.11, lowest-direct, windows-latest)	1m 30s
checks / test (3.13, locked, ubuntu-latest)	1m 2s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 6s
checks / test (3.14, locked, windows-latest)	2m 20s
checks / test (3.11, locked, windows-latest)	1m 33s
checks / test (3.14, lowest-direct, windows-latest)	1m 24s
checks / test (3.10, locked, windows-latest)	1m 30s
checks / test (3.14, locked, ubuntu-latest)	1m 39s
checks / test (3.13, locked, windows-latest)	1m 36s
checks / test (3.14, lowest-direct, ubuntu-latest)	59s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.12, locked, ubuntu-latest)	50s
checks / test (3.13, lowest-direct, windows-latest)	1m 22s
checks / test (3.10, locked, ubuntu-latest)	1m 6s
all-green	2s
	27m 31s

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