chore: update media query styles

Author: abose

src/extensionsIntegrated/Phoenix-live-preview/live-preview.css

@@ -142,6 +142,14 @@
     opacity: 0.35;
 }
 
+.device-size-item-breakpoint-icon {
+    margin-right: 6px;
+    width: 12px;
+    text-align: center;
+    font-size: inherit;
+    color: rgba(100, 180, 255, 0.8);
+}
+
 #livePreviewModeBtn {
     min-width: fit-content;
     display: flex;