fix: Database reserved keyword issue

The fix will use quotes to escape "key", which is column name in the metadata table. Should work for different database types.

Merge https://github.com/google/adk-python/pull/4106

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/4106 from DineshThumma9:fix/mysql-reserved-keyword-issue e39d0d02f3695d6890bc3267417b5dad58f7e8ee
PiperOrigin-RevId: 854411915

src/google/adk/sessions/migration/_schema_check_utils.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """Database schema version check utility."""
+
 from __future__ import annotations
 
 import logging
@@ -32,8 +33,11 @@ def _get_schema_version_impl(inspector, connection) -> str:
   """Gets DB schema version using inspector and connection."""
   if inspector.has_table("adk_internal_metadata"):
     try:
+      key_col = inspector.dialect.identifier_preparer.quote("key")
       result = connection.execute(
-          text("SELECT value FROM adk_internal_metadata WHERE key = :key"),
+          text(
+              f"SELECT value FROM adk_internal_metadata WHERE {key_col} = :key"
+          ),
           {"key": SCHEMA_VERSION_KEY},
       ).fetchone()
       if result:
@@ -49,6 +53,7 @@ def _get_schema_version_impl(inspector, connection) -> str:
           e,
       )
       raise
+
   # Metadata table doesn't exist, check for v0 schema.
   # V0 schema has an 'events' table with an 'actions' column.
   if inspector.has_table("events"):