fix: alembic migration error msg trying to delete constraint on tables (

#11115)

* fix: alembic migration fails by deleting non existent constraint on tables

* Revert "fix: alembic migration fails by deleting non existent constraint on tables"

This reverts commit 3a359b0.

* mantain migration but just for MySQL and add downgrade procedure

* skip the downgrade

superset/migrations/versions/18532d70ab98_fix_table_unique_constraint_in_mysql.py

@@ -27,15 +27,15 @@
 down_revision = "3fbbc6e8d654"
 
 from alembic import op
+from sqlalchemy.dialects.mysql.base import MySQLDialect
 
 
 def upgrade():
-    try:
+    bind = op.get_bind()
+    if isinstance(bind.dialect, MySQLDialect):
         # index only exists in mysql db
         with op.get_context().autocommit_block():
             op.drop_constraint("table_name", "tables", type_="unique")
-    except Exception as ex:
-        print(ex)
 
 
 def downgrade():