Recent reverting of changes to cursor grabbing intended to match
Blender 3.3 release. This is the case for 3.4x branch, however there is
an additional change to grabbing on WIN32 by Germano [0] which is a
significant improvement on old grabbing logic for Windows.
So instead of matching 3.3x behavior, restore logic that keeps
the cursor centered while grabbing & hidden.
This re-introduces T102792 issue displaying the paint-brush while
dragging buttons, this will have to be solved separately.
Re-apply [1] & [2], revert [3] & [4].
[4]: a3a9459050
[0]: 9fd6dae793
[1]: 4cac8025f0
[2]: 230744d6fd
[3]: 0240b89599
79a34758f5