fix(input, searchbar, textarea): ensure nativeInput is always available (#28362)

Issue number: resolves #28283 

---------

<!-- Please do not submit updates to dependencies unless it fixes an
issue. -->

<!-- Please try to limit your pull request to one type (bugfix, feature,
etc). Submit multiple pull requests if needed. -->

## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

`getInputElement()` is used to access the native input. If the component
has yet to render, then the function will return `undefined`. This
happens mostly when using `ref` on React.

```tsx
<IonInput ref={async input => {
  const nativeInput = await input.getInputElement();
  // nativeInput is undefined
}} />
```

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

- `getInputElement()` will wait to return once the component is ready.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this introduces a breaking change, please describe the impact
and migration path for existing applications below. -->


## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

Dev build: `7.5.1-dev.11697488622.175c9183`