DisplaySettings: Remove redundant text_alignment property from GML

Previously, this was causing an error to be shown on the debug console,
as `CenterMiddle` is not a valid value for this property.

Userland/Applications/DisplaySettings/MonitorSettings.gml

@@ -54,7 +54,6 @@
             @GUI::Label {
                 name: "display_dpi"
                 text: "96 dpi"
-                text_alignment: "CenterMiddle"
                 fixed_width: 50
             }
         }