feat: fix the problem of form entries being deleted when adding a new line #918 and clear the selection box to delete the corresponding edge (#1301)

### What problem does this PR solve?
feat: clear the selection box to delete the corresponding edge. #918
feat: fix the problem of form entries being deleted when adding a new
line #918

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/flow/utils.ts

@@ -173,7 +173,8 @@ export const getOperatorTypeFromId = (id: string | null) => {
 
 // restricted lines cannot be connected successfully.
 export const isValidConnection = (connection: Connection) => {
-  return RestrictedUpstreamMap[
+  const ret = RestrictedUpstreamMap[
     getOperatorTypeFromId(connection.source) as Operator
   ]?.every((x) => x !== getOperatorTypeFromId(connection.target));
+  return ret;
 };