feat: Automated regeneration of discoveryengine v1beta client #47756

Job	Run time
CI (windows-latest, 4.0, --include-spec)	2m 7s
CI (macos-latest, 4.0, --include-spec)	48s
CI (ubuntu-latest, 3.3, --include-spec)	49s
CI (ubuntu-latest, 3.4, --include-spec)	45s
CI (ubuntu-latest, 4.0, --include-spec --include-yardoc --include-build, --enable-frozen-string-l...	1m 32s
CI (ubuntu-latest, 3.2, --include-spec)	45s
	6m 46s

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