chore(core): type checking for unit tests (#28529)

Issue number: N/A

---------

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issue. -->

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## What is the current behavior?
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Type checking inside of the Stencil unit tests have been disabled for a
long time. This has resulted in a difficult developer experience and
numerous issues (both types and implementation) within our unit tests.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- Type checking is now enabled for all Stencil unit tests
- Tests have been updated to resolve type errors and implementation
errors
- Many `as any` casts were introduced, as many legacy tests test invalid
configurations of functions that require it (for example passing
`undefined` to an argument that cannot be `undefined`).

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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and migration path for existing applications below. -->


## Other information

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screenshots of how the component looks before and after the change. -->

To test this PR you can checkout the branch locally. Install
dependencies in the `/core` directory to make sure you are on at least
`@stencil/core@4.7.2`.

Opening either a `.spec.ts` or `.spec.tsx` file, validate that your IDE
detects types and can provide auto completions for jest global types.

If you desire, you can provide an invalid type and try building the
project - you will observe the build will fail due to the invalid type.

core/src/components/action-sheet/test/basic/action-sheet.spec.tsx

@@ -7,10 +7,17 @@ describe('action sheet: htmlAttributes inheritance', () => {
   it('should correctly inherit attributes on host', async () => {
     const page = await newSpecPage({
       components: [ActionSheet],
-      template: () => <ion-action-sheet htmlAttributes={{ 'data-testid': 'basic-action-sheet' }}></ion-action-sheet>,
+      template: () => (
+        <ion-action-sheet
+          htmlAttributes={{
+            'data-testid': 'basic-action-sheet',
+          }}
+          overlayIndex={1}
+        ></ion-action-sheet>
+      ),
     });
 
-    const actionSheet = page.body.querySelector('ion-action-sheet');
+    const actionSheet = page.body.querySelector('ion-action-sheet')!;
 
     await expect(actionSheet.getAttribute('data-testid')).toBe('basic-action-sheet');
   });