[breaking] gRPC `UpdateIndex` and `UpdateLibrariesIndex` improvements #4300

Job	Run time
run-determination	1s
check-config (./)	27s
check-formatting (./)	10s
check-license-headers (./)	34s
check-outdated (./)	28s
check-style (./)	42s
build (internal/arduino/discovery/discovery_client)	14s
build (rpc/internal/client_example)	13s
build (commands/daemon/term_example)	22s
	3m 11s

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