Fix MySQL related E2E failures (#9466)

test/e2e-v2/script/prepare/setup-oap/download-mysql.sh

@@ -21,6 +21,11 @@ SW_HOME=/skywalking
 MYSQL_URL="https://repo.maven.apache.org/maven2/mysql/mysql-connector-java/8.0.13/mysql-connector-java-8.0.13.jar"
 MYSQL_DRIVER="mysql-connector-java-8.0.13.jar"
 
+# ensure the curl command been installed
+if ! command -v curl &> /dev/null; then
+    apt update -y && apt install -y curl
+fi
+
 if ! curl -Lo "${SW_HOME}/oap-libs/${MYSQL_DRIVER}" ${MYSQL_URL}; then
     echo "Fail to download ${MYSQL_DRIVER}."
     exit 1