Remove true center mode and border mode (#20587)
Fixes #20073
Fixes #20501
Fixes #20499
Summary of the issue:
True center mode doesn't work fully.
When disabling clamping from center mode or border mode on win 11, the taskbar can't be interacted with.
When enabling clamping on border or relative mode on win 11, you can't even reach the taskbar.
This makes border mode unusable on win 11 for mouse users.
Description of user facing changes:
Remove true center mode from the options, instead clamping/not clamping where appropriate.
Description of developer facing changes:
No public API changes since 2026.1.X
Description of development approach:
Remove true center mode, instead enable clamping based on full screen mode.
Remove border mode from full screen modes.
Added profile upgrade steps
