fix(modal): improve card modal background transition from portrait to landscape (#30551)

Issue number: resolves internal

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## What is the current behavior?
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Currently, if you have multiple card modals open in portrait view and
then transition to landscape, the background will not be transformed
properly and will not cover the entire screen as expected.


https://github.com/user-attachments/assets/bb2c7015-adb6-4c3b-8bc5-13360275fcf4


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

Now, we're correctly targeting the right element and will transform it
as expected. This allows a more consistent UX for these transitions.



https://github.com/user-attachments/assets/fff72387-d78b-4df4-a234-d89b54f694c4



## Does this introduce a breaking change?

- [ ] Yes
- [X] No

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## Other information

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

[Relevant (broken) screen (main
branch)](https://ionic-framework-git-main-ionic1.vercel.app/src/components/modal/test/card?ionic:mode=ios)

[Relevant (fixed) screen (this
branch)](https://ionic-framework-git-fix-modal-landscape-background-ionic1.vercel.app/src/components/modal/test/card?ionic:mode=ios)