feat: remove css animations support for ionic animations (#29123)

Issue number: Internal

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## What is the current behavior?
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Ionic Framework provides a small utility wrapper around the Web
Animations API. Historically not all browsers that Ionic Framework
supported, had support for the Web Animations API. To offer backwards
compatibility, Ionic Framework provided fallback behaviors for the
different wrapped APIs.


## What is the new behavior?
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this PR. -->

- Removes the legacy CSS animations fallback behavior from the Web
Animations API animation utility. Maintaining a few no-op behaviors for
test environments.
- Resolved a few internal type usages that were casting to any
- Removed spec tests that were testing the fallback CSS animations
behavior and/or already had test coverage from other unit tests.

## Does this introduce a breaking change?

- [x] Yes
- [ ] No

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All modern browsers support the Web Animations API today. If a developer
needs to target an older browser that does not support Web Animations,
they should either use [a
polyfill](https://github.com/web-animations/web-animations-js), or
implement the fallback behavior themselves.

## Other information

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

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Co-authored-by: Liam DeBeasi <liamdebeasi@users.noreply.github.com>