fix(upgrade): remove unused version export (#33180)

In some module systems (Closure), it's illegal to mutate an export.
This mutated export isn't used anyway, so we can just remove it.

PR Close #33180

packages/upgrade/src/dynamic/test/upgrade_spec.ts

@@ -29,7 +29,8 @@ withEachNg1Version(() => {
     afterEach(() => destroyPlatform());
 
     describe('(basic use)', () => {
-      it('should have AngularJS loaded', () => expect(angular.version.major).toBe(1));
+      it('should have AngularJS loaded',
+         () => expect(angular.getAngularJSGlobal().version.major).toBe(1));
 
       it('should instantiate ng2 in ng1 template and project content', async(() => {
            const ng1Module = angular.module_('ng1', []);