fix(media-check) use current theme colors

[david-allison]

Note

This PR was part of the swe-productivity research study.
My review was performed: swe-productivity#11
I have cherry-picked these commits and fixed up compile errors due to conflicts

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Purpose / Description

The MediaCheck screen uses a web view, but doesn't apply and styling to the view. I've added some simple syling,
pulling colors from the current theme.

Fixes

• Fixes Check media background doesn't match the theme #18594

Approach

I added code to fetch the text and background colors from the current theme, and add them to the inline
styles in the HTML content.

How Has This Been Tested?

Reproduction steps:

• From the main view, select Check > Check Media from the overflow menu
• Select Ok in the prompt

The media check view previously always showed black text on a white background, but with these changes, it
now uses the text and background colors from the currently selected theme.

Before:

After

Checklist

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[criticalAY]

Cool!