tuist bazel setup probes remote cache availability before writing config

tuist bazel setup now probes the resolved remote cache endpoint via Bazel’s REAPI GetCapabilities over gRPC before writing .bazelrc.tuist, regardless of whether the URL came from the server or a TUIST_CACHE_ENDPOINT override. If the probe cannot reach the cache, authenticate, or authorize the instance, setup fails fast with a clear error and writes no config, so Bazel builds no longer crash on the first invocation against a misconfigured or unreachable cache.