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/common/src/angular1.ts

@@ -280,7 +280,6 @@ export function getAngularLib(): any {
  */
 export function setAngularJSGlobal(ng: any): void {
   angular = ng;
-  version = ng && ng.version;
 }
 
 /**
@@ -309,5 +308,3 @@ export const injector: typeof angular.injector =
 export const resumeBootstrap: typeof angular.resumeBootstrap = () => angular.resumeBootstrap();
 
 export const getTestability: typeof angular.getTestability = e => angular.getTestability(e);
-
-export let version = angular.version;

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', []);

packages/upgrade/static/test/integration/examples_spec.ts

@@ -23,7 +23,8 @@ withEachNg1Version(() => {
     beforeEach(() => destroyPlatform());
     afterEach(() => destroyPlatform());
 
-    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 verify UpgradeAdapter example', async(() => {