ci: disable github-backed bazel cache on self-hosted runners

Disables GitHub-backed caching (bazelisk-cache, disk-cache,
repository-cache) in setup-bazel for all CI jobs. The self-hosted
runners already have a local persistent .bazelrc configuration, so
we can rely on that to avoid network overhead, rate limits, and
cache conflicts when multiple runners run on the same machine.

Signed-off-by: Miguel Osorio <miguelosorio@google.com>

.github/workflows/ci.yml

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 82dace0..ede19ca 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,9 +22,9 @@
     - name: Setup Bazel
       uses: bazel-contrib/setup-bazel@0.19.0
       with:
-        bazelisk-cache: true
-        disk-cache: true
-        repository-cache: true
+        bazelisk-cache: false
+        disk-cache: false
+        repository-cache: false
 
     - name: Presubmit Checks
       # The presubmit workflow performs formatting checks, license checks
@@ -42,9 +42,9 @@
     - name: Setup Bazel
       uses: bazel-contrib/setup-bazel@0.19.0
       with:
-        bazelisk-cache: true
-        disk-cache: true
-        repository-cache: true
+        bazelisk-cache: false
+        disk-cache: false
+        repository-cache: false
 
     - name: Run tests
       # See workflows.json for the `ci` definition.
@@ -61,9 +61,9 @@
     - name: Setup Bazel
       uses: bazel-contrib/setup-bazel@0.19.0
       with:
-        bazelisk-cache: true
-        disk-cache: true
-        repository-cache: true
+        bazelisk-cache: false
+        disk-cache: false
+        repository-cache: false
 
     - name: Build
       # See workflows.json for the `default` definition.