chore: stabilize MySQL tests by aligning isolation levels (#28028)

.github/workflows/bashlib.sh

@@ -89,6 +89,8 @@ EOF
 setup-mysql() {
   say "::group::Initialize database"
   mysql -h 127.0.0.1 -P 13306 -u root --password=root <<-EOF
+    SET GLOBAL transaction_isolation='READ-COMMITTED';
+    SET GLOBAL TRANSACTION ISOLATION LEVEL READ COMMITTED;
     DROP DATABASE IF EXISTS superset;
     CREATE DATABASE superset DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci;
     DROP DATABASE IF EXISTS sqllab_test_db;

.github/workflows/superset-python-integrationtest.yml

@@ -29,6 +29,11 @@ jobs:
           MYSQL_ROOT_PASSWORD: root
         ports:
           - 13306:3306
+        options: >-
+          --health-cmd="mysqladmin ping --silent"
+          --health-interval=10s
+          --health-timeout=5s
+          --health-retries=5
       redis:
         image: redis:7-alpine
         options: --entrypoint redis-server