Blender Git Loki

Fix library name clipping most of the data-block name in data-block menus

Issue is visible here https://developer.blender.org/F8626313.

If there is enough space for both the item name and the library hint, display
both. Otherwise, clip either the item name, the library hint, or both so that
not more than 60% and 40% of the available width are used repectively.
There are further improvements we could do, as noted in T84188, this just fixes
the regression for the release.

Part of T84188. There were multiple reports about this, see merged in and
mentioned reports in T84188 and T78012.