Allow the UDIM grid to be shown and adjusted when there are images loaded in UV edit mode. Right now the grid feature disappears once an image is loaded and many have found this to be confusing. Based on community and artist feedback, there was support to change this behavior[1] This patch does the following: - Allows the grid to be shown even when images are present - The max allowable dimensions for the grid has been increased from 10x10 to 10x100 to match the underlying maximum UDIM range that blender supports Note: This should not affect other Image editor modes like Paint/Mask or the Render Result viewer etc. Future work in this area is currently documented in a dedicated design task[2] [1] https://devtalk.blender.org/t/the-udim-tile-grid-design-and-feedback-thread/20136 [2] https://developer.blender.org/T90913 Differential Revision: https://developer.blender.org/D11860