Promote ServiceExternalIP to beta #35243

Job	Run time
Check whether tests need to be run based on diff	14s
Verify docs and spelling	31s
Unit test (ubuntu-latest)	7m 58s
Unit test (windows-2022)	17m 14s
Golangci-lint (macos-latest)	5m 10s
Build Antrea and antctl binaries	13m 12s
Golangci-lint (ubuntu-latest)	9m 36s
Integration test	5m 46s
Build Antrea Windows binaries	2m 17s
Go benchmark test	5m 22s
Check tidy, code generation and manifest	4m 35s
	1h 11m 55s

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