Use collect_str for FunctionSelector serialization #10014

Job	Run time
clippy	2m 4s
wasm-unknown	2m 41s
typos	7s
wasm-wasi	4m 21s
check no_std	59s
feature-checks	9m 58s
doctest	3m 30s
docs	2m 18s
fmt	18s
Analyze (actions)	48s
feature-propagation	1m 11s
deny / cargo deny check	22s
test windows-latest stable	5m 42s
test ubuntu-latest 1.88 --no-default-features -F reqwest-rustls-tls	1m 20s
test ubuntu-latest nightly --no-default-features -F reqwest-rustls-tls	2m 55s
test ubuntu-latest nightly	3m 4s
test ubuntu-latest nightly --all-features	4m 5s
test ubuntu-latest stable	3m 53s
test windows-latest nightly --no-default-features -F reqwest-rustls-tls	5m 33s
test windows-latest stable --no-default-features -F reqwest-rustls-tls	6m 21s
test ubuntu-latest stable --no-default-features -F reqwest-rustls-tls	3m 53s
test windows-latest stable --all-features	7m 14s
test windows-latest 1.88 --no-default-features -F reqwest-rustls-tls	2m 57s
test ubuntu-latest 1.88	1m 36s
test ubuntu-latest stable --all-features	4m 30s
test windows-latest nightly --all-features	7m 53s
test windows-latest 1.88	4m 8s
test windows-latest nightly	6m 4s
ci success	4s
	1h 39m 49s

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