feat(transport): Make tower internal dependency #3566

Job	Run time
cargo-deny check	23s
clippy	1m 21s
rustfmt	12s
codegen	38s
check-external-types	59s
Check MSRV	51s
Interop Tests (ubuntu-latest)	52s
check (ubuntu-latest)	2m 48s
Interop Tests (macOS-latest)	1m 22s
semver	51s
check (macOS-latest)	3m 23s
Interop Tests (windows-latest)	2m 39s
test (ubuntu-latest)	3m 8s
check (windows-latest)	4m 27s
test (macOS-latest)	2m 17s
test (windows-latest)	5m 21s
Check unused dependencies	4m 2s
	35m 34s

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