ci: add yarn cache for material-unit tests job (#29378)

PR Close #29378

scripts/ci/clone_angular_material_repo.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+set -u -e -o pipefail
+
+# Ensure that the temporary directory does not exist.
+rm -rf ${MATERIAL_REPO_TMP_DIR}
+
+# Clone the Material repository into the given temporary directory.
+git clone --depth 1 --branch ${MATERIAL_REPO_BRANCH} ${MATERIAL_REPO_URL} \
+  ${MATERIAL_REPO_TMP_DIR}