Pin TF-GNN's Kokoro tests to bazel 7.4.1 (last before 8.0.0).

PiperOrigin-RevId: 716125769

Author: arnoegw

kokoro/github/ubuntu/cpu/build.sh

@@ -14,6 +14,7 @@
 # limitations under the License.
 
 set -e
+set -u
 set -x
 
 cd "${KOKORO_ARTIFACTS_DIR}/github/gnn/"
@@ -36,6 +37,8 @@ mkdir -p "$TEST_ROOT"
 ln -s "$(pwd)"/tensorflow_gnn "$TEST_ROOT"/tensorflow_gnn
 tag_filters="-no_oss,-oss_excluded"
 
+chmod +x "${KOKORO_GFILE_DIR}/use_bazel.sh"
+"${KOKORO_GFILE_DIR}/use_bazel.sh" 7.4.1  # Last before 8.0.0
 bazel clean
 pip install -r requirements-dev.txt --progress-bar off
 pip install tf-keras-nightly tf-nightly --progress-bar off --upgrade

kokoro/github/ubuntu/cpu/build_versioned.sh

@@ -14,6 +14,7 @@
 # limitations under the License.
 
 set -e
+set -u
 set -x
 
 cd "${KOKORO_ARTIFACTS_DIR}/github/gnn/"
@@ -47,6 +48,8 @@ cat /etc/os-release
 # These tag filters are enforced to start with a comma for separation
 tag_filters="-no_oss,-oss_excluded${TAG_FILTERS}"
 
+chmod +x "${KOKORO_GFILE_DIR}/use_bazel.sh"
+"${KOKORO_GFILE_DIR}/use_bazel.sh" 7.4.1  # Last before 8.0.0
 bazel clean
 pip install -r requirements-dev.txt --progress-bar off
 pip install tensorflow=="${TF_VERSION}" --progress-bar off --upgrade

tensorflow_gnn/__init__.py

@@ -42,6 +42,7 @@ def _check_keras_version():
           "For more information, see "
           "https://github.com/tensorflow/gnn/blob/main/tensorflow_gnn/docs/guide/keras_version.md"
       )
+
 _check_keras_version()
 del _check_keras_version
 # pylint: enable=g-statement-before-imports