fix(migrations): Remove unhelpful parsing errors from the log (angular#52401)

When running the control flow migration, unhelpful ICU parsing errors were being logged and creating a bunch of noise for users.

PR Close angular#52401

Author: thePunderWoman

packages/core/schematics/ng-generate/control-flow-migration/util.ts

@@ -107,13 +107,9 @@ export function migrateTemplate(template: string): {migrated: string|null, error
 
     // Don't migrate invalid templates.
     if (parsed.errors && parsed.errors.length > 0) {
-      for (let error of parsed.errors) {
-        errors.push({type: 'parse', error});
-      }
       return {migrated: null, errors};
     }
-  } catch (error: unknown) {
-    errors.push({type: 'parse', error});
+  } catch {
     return {migrated: null, errors};
   }
 

packages/core/schematics/test/control_flow_migration_spec.ts

@@ -1963,7 +1963,7 @@ describe('control flow migration', () => {
 
         @Component({
           imports: [NgIf],
-          template: \`<div><span *ngIf="toggle>This should be hidden</span></div>\`
+          template: \`<div><span *ngIf="toggle">This should be hidden</span></div>\`
         })
         class Comp {
           toggle = false;
@@ -1973,7 +1973,8 @@ describe('control flow migration', () => {
       await runMigration();
       tree.readContent('/comp.ts');
 
-      expect(warnOutput.join(' ')).toContain('WARNING: 1 errors occured during your migration');
+      expect(warnOutput.join(' '))
+          .toContain('IMPORTANT! This migration is in developer preview. Use with caution.');
     });
   });