aria-label for native button element inside ic-button does not get updated if value changes

@ad9242 is already working on this.

Since Oct 20, 2023.

## Summary of the bug
If you set an aria-label on an ic-button and then subsequently change the value, the native button element inside does not get update with the new value, causing screen readers to read the wrong value.

## 🪜 How to reproduce
Tell us the steps to reproduce the problem:
1. set the aria-label attribute on an ic-button
2. later change the attribute to another value
3. inspect the element in browser dev tool
4. the aria label is still set to the original value

## 📸 Screenshots or code

## 🖥 📱 Device
All

## 🧐 Expected behaviour
The aria-label should be updated

## 📝 Acceptance Criteria
If relevant, describe in full detail the different interactions and edge cases that the component or patterns needs to fulfil.

*Given* an aria label is updated on an ic-button component
*When* a user focus the button with a screen reader enabled
*Then* the updated label should be read by the screen reader

We should also enhance the a11y tests to make sure this is tested.

## Additional info
For aria-describedby, a mutation observer was added to watch when the value changes. A similar approach may be possible to resolve this

Alternatively, moving to stencil 4.3.0 may allow us to make use of watching native HTML attributes: https://github.com/ionic-team/stencil/pull/4760

This is needed for DatePicker component.