Revert "Enable Vim/Helix keybindings when the base keymap is set to None" (#55144)

Reverts zed-industries/zed#54899

Release notes:

- Reverted the "none" keymap to be literally nothing
54ee3c1b0cConrad Irwin committed on 4/29/2026, 7:33:12 AM· committed by GitHubparent6357a85
1 file changedLine totals unavailable