feat(select): add dark mode support for <pf-select>

[dali327519294]

What I did

Fixed bug RedHat-UX/red-hat-design-system#2681

1.Added dark mode support for <pf-select> to ensure proper contrast and accessibility in both light and dark themes.

Testing Instructions

1. Open the <pf-select> demo page.
2. Switch between light and dark color schemes (using the browser or system setting).
3. Verify that the dropdown, text, and border colors adjust correctly.

Notes to Reviewers

1. No breaking changes.
2. Added a changeset for minor version bump.
3. Verified behavior manually in both modes.

[changeset-bot]

🦋 Changeset detected

Latest commit: 70377f6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@patternfly/elements	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[dali327519294]

Hi @bennypowers 👋
Requesting a code review for the <pf-select> dark mode support PR.
Thanks in advance for taking a look! 🙏

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[dali327519294]

Added basic Dark Mode support using @media (prefers-color-scheme: dark) and PatternFly global variables.

The Goal: To ensure the component is future-proofed and ready to display correctly in dark themes when PatternFly officially implements Dark Mode across the ecosystem.

Fixed bug 2681#

[bennypowers]

@zeroedin has an approach in RedHat-UX/red-hat-design-system#2681. if we update PFE there to v4.2.0, we can hack around this in RHDS without having to introduce light/dark to PFE here.

RedHat-UX/red-hat-design-system#2684 (comment)