build(aio): don't constrain checkContentRules to run before another processor (#24000)

We don't really care when this processor runs as long as it happens
after the tags have been extracted.
By not constraining its `runBefore` property we can ensure that other
processors can be run before it.

PR Close #24000

aio/tools/transforms/angular-base-package/processors/checkContentRules.spec.js

@@ -18,7 +18,7 @@ describe('checkContentRules processor', function() {
 
   it('shpuld run at the right time', () => {
     expect(processor.$runAfter).toEqual(['tags-extracted']);
-    expect(processor.$runBefore).toEqual(['processing-docs']);
+    expect(processor.$runBefore).toEqual([]);
   });
 
   it('should do nothing if not configured', () => {