Add `ActiveValue::try_as_ref()` #4207

Job	Run time
Init	2s
Unit Test	3m 19s
Clippy	1m 15s
Examples (examples/actix_example)	2m 32s
Rustfmt	18s
Examples (examples/axum_example)	2m 22s
Examples (examples/basic)	1m 15s
Examples (examples/graphql_example)	2m 46s
Examples (examples/jsonrpsee_example)	2m 37s
Examples (examples/loco_example)	3m 16s
Examples (examples/poem_example)	2m 25s
Examples (examples/proxy_gluesql_example)	1m 23s
Examples (examples/rocket_example)	3m 9s
Examples (examples/rocket_okapi_example)	3m 21s
Examples (examples/salvo_example)	2m 49s
Examples (examples/seaography_example)	2m 33s
Examples (examples/tonic_example)	2m 27s
Compile MySQL (actix, native-tls)	2m 46s
Compile MySQL (actix, rustls)	3m 5s
Compile SQLite (async-std, native-tls)	3m 2s
Compile PostgreSQL (tokio, native-tls)	2m 58s
Compile SQLite (async-std, rustls)	2m 58s
CLI	0s
Compile PostgreSQL (tokio, rustls)	3m 3s
Issues Matrix	0s
Issues	0s
SQLite (async-std, native-tls)	4m 27s
SQLite (async-std, rustls)	4m 30s
MariaDB (10.6, actix, native-tls)	2m 17s
MySQL (8, actix, native-tls)	3m 26s
MySQL (5.7, actix, native-tls)	3m 40s
Postgres (14.4, tokio, native-tls)	6m 42s
	1h 20m 43s

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