Blender Git Loki

Fix T87749 (partially): Text jitter in buttons and spreadsheet editor

This patch fixes jittering text when resizing regions of the UI as
described in T87749. The jitter was caused by the text padding
being stored as an integer which lead to inconsistent rounding.

Most notably this patch fixes the jitter in the new spreadsheet editor,
but not all occurrences of jitter described in T87749 (e.g. in UI lists)
are addressed.

Differential Revision: https://developer.blender.org/D11060