http,inspector: add WebSocket upgrade observability #5889

Job	Run time
Build slim tarball	2m 55s
x86_64-darwin: with shared libraries	43m 25s
aarch64-darwin: with shared libraries	29m 6s
x86_64-linux: with shared libraries	27m 52s
aarch64-linux: with shared libraries	22m 49s
	2h 6m 7s

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