gui: remove config.dpi override logic

The overrides are now applied at the window layer, which is (mostly!)
aware of per-screen overrides.

refs: #4096

wezterm-gui/src/termwindow/resize.rs

@@ -20,10 +20,6 @@ impl super::TermWindow {
         window: &Window,
         live_resizing: bool,
     ) {
-        // ignore dpi changes if there is a fixed dpi set in configuration
-        if let Some(dpi) = configuration().dpi {
-            dimensions.dpi = dpi as usize;
-        }
         log::trace!(
             "resize event, live={} current cells: {:?}, current dims: {:?}, new dims: {:?} window_state:{:?}",
             live_resizing,