Update methods to create `FromFnLayer` #4894

Job	Run time
cargo-hack	5m 7s
check	1m 40s
check-docs	30s
cargo-public-api-crates (axum)	30s
cargo-public-api-crates (axum-core)	17s
dependencies-are-sorted	15s
Spell Check with Typos	4s
cargo-public-api-crates (axum-extra)	38s
cargo-deny check (advisories)	23s
cargo-public-api-crates (axum-macros)	23s
cargo-deny check (bans licenses sources)	26s
armv5te-unknown-linux-musleabi	42s
test-docs	1m 32s
test-nightly	1m 42s
test-msrv	2m 33s
test-versions (stable)	2m 53s
wasm32-unknown-unknown	22s
test-versions (beta)	2m 48s
	22m 45s

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