Android: divider paints a hard-coded light grey instead of the theme's outline colour

[sandermj]

Package: nativephp/mobile-ui 0.4.0, reproduces on current main
Platform: Android

A PR follows this issue.

Steps to reproduce

Place a <divider /> between rows on a dark surface.

Expected: a subtle hairline, like iOS's system separator, which dims in dark mode.

Actual: a bright #E0E0E0 line.

Cause

DividerRenderer in SimpleRenderers.kt uses that constant whenever no border colour is authored, although the theme already defines outline-variant for exactly this purpose.

Proposed fix

Fall back to NativeUITheme.{dark,light}.outlineVariant, the way the chip, checkbox and button-group renderers already fall back to theme.outline. An authored border colour still wins.

Files involved

resources/android/SimpleRenderers.kt.