revert background colour in main.js (+1 squashed commit)

Squashed commits:
[9ec61f5f] revert background colour

main.js

@@ -215,10 +215,6 @@ function createWindow() {
       minWidth: MIN_WIDTH,
       minHeight: MIN_HEIGHT,
       autoHideMenuBar: false,
-      backgroundColor:
-        config.environment === 'test' || config.environment === 'test-lib'
-          ? '#ffffff' // Tests should always be rendered on a white background
-          : '#2090EA',
       webPreferences: {
         nodeIntegration: false,
         nodeIntegrationInWorker: false,

stylesheets/_global.scss

@@ -459,7 +459,7 @@ $loading-height: 16px;
   right: 0;
   top: 0;
   bottom: 0;
-  background-color: $color-signal-blue;
+  background-color: white;
   color: $color-white;
   display: flex;
   align-items: center;