fix(@schematics/angular): handle existence of un-referenced library prod tsconfig

Author: alan-agius4

packages/schematics/angular/migrations/update-9/ivy-libraries.ts

@@ -114,5 +114,7 @@ function createTsConfig(tree: Tree, tsConfigPath: string) {
  },
  };
 
- tree.create(tsConfigPath, JSON.stringify(tsConfigContent, undefined, 2));
+ if (!tree.exists(tsConfigPath)) {
+ tree.create(tsConfigPath, JSON.stringify(tsConfigContent, undefined, 2));
+ }
 }

packages/schematics/angular/migrations/update-9/ivy-libraries_spec.ts

@@ -59,6 +59,8 @@ describe('Migration to version 9', () => {
  tree,
  )
  .toPromise();
+
+ tree.delete(libProdTsConfig);
  });
 
  it(`should add 'tsConfig' option in production when configurations doesn't exists`, async () => {