feat: add type_generic and is_dttm to table metadata (#14863)

superset-frontend/src/datasource/DatasourceEditor.jsx

@@ -379,6 +379,7 @@ class DatasourceEditor extends React.PureComponent {
   }
 
   setColumns(obj) {
+    // update calculatedColumns or databaseColumns
     this.setState(obj, this.validateAndChange);
   }
 
@@ -414,13 +415,18 @@ class DatasourceEditor extends React.PureComponent {
           type: col.type,
           groupby: true,
           filterable: true,
+          is_dttm: col.is_dttm,
         });
         results.added.push(col.name);
-      } else if (currentCol.type !== col.type) {
+      } else if (
+        currentCol.type !== col.type ||
+        currentCol.is_dttm !== col.is_dttm
+      ) {
         // modified column
         finalColumns.push({
           ...currentCol,
           type: col.type,
+          is_dttm: col.is_dttm,
         });
         results.modified.push(col.name);
       } else {