Add version_removed for theme-color for Safari

[jackwellerreal]

Summary

Added version_removed to the theme-color metadata tag for Safari 26

Test results and supporting details

See https://caniuse.com/?search=theme-color

[github-actions]

Tip: Review these changes grouped by change (recommended for most PRs), or grouped by feature (for large PRs).

[caugner]

See caniuse.com?search=theme-color

Note that caniuse states:

Supported, but does not actually use the color anywhere.

WebKit appears to handle the meta theme-color (https://github.com/search?q=repo%3AWebKit%2FWebKit+%2Ftheme-color%2F+path%3ASource%2FWebCore&type=code), but it doesn't seem to do more than setting a flag (https://github.com/search?q=repo%3AWebKit%2FWebKit%20%2Fm_pendingThemeColorChange%2F&type=code).

However, the spec does not actually impose any behavior (emphasis mine):

The value must be a string that matches the CSS production, defining a suggested color that user agents should use to customize the display of the page or of the surrounding user interface. For example, a browser might color the page's title bar with the specified value, or use it as a color highlight in a tab bar or task switcher.

Assuming that Chrome Android uses the theme-color, it might make sense to extract a subfeature that captures this behavior.

However, marking Safari as not supporting this feature does not seem right.

@jackwellerreal Could you file an issue instead? 🙏