feat: expose encoded_len_with_signature() #3253

Job	Run time
test ubuntu-latest stable --no-default-features	1m 21s
test ubuntu-latest stable	1m 19s
doctest	1m 7s
test ubuntu-latest nightly --no-default-features	1m 9s
no-std	18s
wasm-unknown	41s
test ubuntu-latest nightly	1m 24s
wasm-wasi	58s
test ubuntu-latest 1.76 --no-default-features	54s
test ubuntu-latest 1.76	35s
test windows-latest stable --no-default-features	5m 15s
cfg-check	22s
test windows-latest stable	4m 37s
clippy	36s
test windows-latest nightly --no-default-features	4m 34s
docs	58s
test windows-latest nightly	4m 11s
feature-checks	3m 8s
test windows-latest 1.76 --no-default-features	4m 11s
fmt	12s
test windows-latest 1.76	2m 33s
	40m 23s

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