Fix build breakage by disabling fuzzer

rust/uwb_core/fuzz/proto_uwb_service_fuzzer.rs does not build successfully due to a missing crate. This will disable it while dependencies are fixed.
The failing build is haiku_fuzzcoverage_shiba-trunk_staging-userdebug on git_main-throttled-haiku.

Test: Build success after disabling fuzzer.
Bug: 343535930
Change-Id: I33cb1566b98fcef0c6f817314b43d0c13c1a9ec0