Fixes for settings issues

[x] ~~When changing keybind for OpenMap (in PlayerController category) to alt+m and pressing apply, then back, then settings again it shows original keybind.~~
[x] The dialog that shows when changes require restarting needs a background - use same one as the dialogs used to have. Also the other dialogs seem to have lost their background, e.g. the one that shows when modifying settings and pressing back button.
[x] When changing FSR-Upsampling setting I get warning "Failed to change value[ESettingValueType::CurrentValue] of the setting[FSRUpsampling], due to CanBeModified returning false." Also when I press back I don't get dialog to confirm if I want to save changes.
[x] I got into a state where I can't disable FSR FI or enable DLSS-FG. Clicking on either button does nothing. FSR Upsampling is on quality setting. DLSS-FG is off, DLSS-SR is off, reflex is disabled. I get log "DLSSFG : Not Supported" yet I'm on GPU that supports DLSS-FG.
[x] On quit confirmation dialog, if you press no it should revert the settings that were changed.

HaywireInteractive / OnAllFronts-Public