Blender Git Loki

UI: Add highlight arguments to tab buttons

This adds arguments to `uiLayout.prop_tabs_enum` and the C equivalent
(`uiItemTabsEnumR_prop`) to gray out tabs based on a boolean array.

For property search in multiple tabs, we need a way to show which tabs
have a search result, but we still need to show which tab is active.

Differential Revision: https://developer.blender.org/D8858