fix: switch to FREEPDB1 container before granting DBMS_LOCK

The test user is created in the FREEPDB1 pluggable database,
so we need to switch to that container before granting permissions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: tanbro

.github/workflows/python-package.yml

@@ -158,9 +158,12 @@ jobs:
         run: |
           podman exec oracledb sqlplus -s / as sysdba <<'EOF'
           ALTER SESSION SET "_ORACLE_SCRIPT"=TRUE;
+          ALTER SESSION SET CONTAINER=FREEPDB1;
           GRANT EXECUTE ON SYS.DBMS_LOCK TO test;
+          SELECT * FROM dba_tab_privs WHERE table_name = 'DBMS_LOCK' AND grantee = 'TEST';
           exit;
           EOF
+          echo "Grant completed"
 
       - name: Run tests
         shell: bash