fix(bazel): adjust mock of tsconfig for ng_module rule unit test (#20175)

Due to 7f33f01b72

PR Close #20175

packages/bazel/test/ngc-wrapped/tsconfig_template.ts

@@ -64,6 +64,10 @@ export function createTsConfig(options: TsConfigOptions) {
       'es5Mode': true,
       'manifest': createManifestPath(options),
       'compilationTargetSrc': options.compilationTargetSrc,
+      // Override this property from the real tsconfig we read
+      // Because we ask for :empty_tsconfig.json, we get the ES6 version which
+      // expects to write externs, yet that doesn't work under this fixture.
+      'tsickleExternsPath': '',
     },
     'files': options.files,
     'angularCompilerOptions': {