Fix conflicting assertions for click events (facebook#46633)

Summary:
Pull Request resolved: facebook#46633

There is an assertion in the "basic click test" that [checks](https://github.com/facebook/react-native/blob/d6e0bc7/packages/rn-tester/js/examples/Experimental/W3CPointerEventPlatformTests/PointerEventClickTouch.js#L36-L40) that `isPrimary` is set to false. The same assertion suite also does a mouse event [validation](https://github.com/facebook/react-native/blob/d6e0bc7/packages/rn-tester/js/examples/Experimental/W3CPointerEventPlatformTests/PointerEventSupport.js#L201-L204) that `isPrimary` is set to true.

This fixes the conflicting assertions, favoring the behavior observed on Web, that `isPrimary` for mouse click events should be set to false.

## Changelog

[General][Fixed] Fixed issues with W3C PointerEvents tests

Differential Revision: D63336622

packages/rn-tester/js/examples/Experimental/W3CPointerEventPlatformTests/PointerEventClickTouch.js

@@ -65,7 +65,11 @@ function PointerEventClickTouchTestCase(props: PlatformTestComponentBaseProps) {
         checkClickEventProperties(assert_equals, e);
       });
 
-      check_PointerEvent(harness, e, 'click', {});
+      // We cannot test mouse pointer events here, as this will assert that
+      // isPrimary is set to true, when it should be false for click events.
+      if (e.nativeEvent.pointerType !== 'mouse') {
+        check_PointerEvent(harness, e, 'click', {});
+      }
       testPointerClick.done();
     },
     [harness, testPointerClick],