Title:

fix(ios): guard against non-string imageURI in createUIImageFromURI

Body:

Summary

When the CSS shorthand property background is used with a plain color value (e.g. background: #1A1A1A), the imageURI parameter passed to createUIImageFromURI in background.ios.ts can be a non-string
type (such as a Color object). This causes imageURI.match(uriPattern) to throw a TypeError at runtime, crashing the application on iOS.

Root Cause

The background CSS shorthand is parsed into multiple sub-properties (background-color, background-image, etc.). In certain cases, a Color object rather than a string is passed through as the imageURI
argument. The existing code assumes imageURI is always a string when truthy, and calls .match() on it directly without a type check.

Fix

Added a typeof imageURI !== 'string' guard before the .match() call. When imageURI is not a string, the function invokes the callback with null and returns early, allowing the rest of the background
rendering pipeline (e.g. background-color) to proceed normally.

if (imageURI) {
if (typeof imageURI !== 'string') {
callback(null);
return;
}
const match = imageURI.match(uriPattern);
// ...
}

How to Reproduce

1. Set a background on any view using the CSS shorthand with a plain color:
   ActionBar {
   background: #1A1A1A;
   }
2. Run on iOS
3. App crashes with TypeError: imageURI.match is not a function

Workaround (before this fix): Replace background with background-color to avoid triggering createUIImageFromURI entirely.

Affected

@nativescript/core