fix(select): ensure select sizes are respected when the label is empty (#30087)

Issue number: internal

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## What is the current behavior?
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Currently, the experience planned for ionic select has the sizes fixed
and should be respected even when the labels are not presented.
https://stackblitz.com/edit/ku3fqz?file=src%2Fmain.tsx

## What is the new behavior?
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this PR. -->
- When select is used with Ionic-theme, the select should respect the
height sizes established.
-
https://stackblitz.com/edit/ku3fqz-2vnasdmx?file=package-lock.json,package.json
-
https://ionic-framework-cdtf7hsqy-ionic1.vercel.app/src/components/select/test/size?ionic:theme=ionic

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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Co-authored-by: Maria Hutt <maria@ionic.io>