Main issue is that the UI doesn not respect the Unified Weight/Strength
setting (but instead alwasy shows the brushes weight/strength)

Was working before, but somewhat missed in rBfb74dcc5d69d?

Here comes the long story (sorry for the extra detour), Gradient Tool in
its current state is not very user friendly:

• generally this accesses previously selected tools brush as it doesnt

have its own brush (so it looks like it has its own settings for
strength/weight, but those are from an 'alien' brush)

• when Unified Weight is turned ON (default) the tool actually works with

the Unified Weight (set on some other brush, e.g. the Draw Brush), but
doesnt present you with that value in the UI (bug!)

• when Unified Weight is turned OFF you are actually tweaking the weight

setting of the previously selected tools brush (the 'alien' one) -- this
causes confusion (it doesnt affect e.g. Blur, Average or Smear since
these dont have weight capabilities)

• this is even worse when tweaking the Strength, you are actually

tweaking the weight setting of the previously selected tools brush (the
'alien' one), this affects Blur, Average or Smear (and Unified Strength is
OFF by default!)

So not sure how to solve the issue with the "tweaking setting of a
seemingly unrelated brush" issue, what I think we should do though is at
least have the values in the UI respect Unified Weight / Unified Strength
since this is what the tool will use internally...

ref T74025