workflows: enable pr review with gemini cli #17586

Job	Run time
dashboard	44s
aux	42s
build	1s
old	49s
gvisor	43s
race	1s
race_dashboard	1s
arch (presubmit_arch_freebsd)	43s
arch (presubmit_arch_openbsd)	45s
arch (presubmit_arch_netbsd)	44s
arch (presubmit_arch_linux)	44s
arch (presubmit_arch_executor)	43s
arch (presubmit_arch_darwin)	44s
arch (presubmit_arch_windows)	44s
	8m 8s

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