fix: z-index for laser pointer to be able to draw on embeds and such (#7918)

packages/excalidraw/components/SVGLayer.scss

@@ -1,3 +1,5 @@
+@import "../css/variables.module.scss";
+
 .excalidraw {
   .SVGLayer {
     pointer-events: none;
@@ -7,7 +9,7 @@
     top: 0;
     left: 0;
 
-    z-index: 2;
+    z-index: var(--zIndex-svgLayer);
 
     & svg {
       image-rendering: auto;

packages/excalidraw/css/styles.scss

@@ -4,6 +4,7 @@
 :root {
   --zIndex-canvas: 1;
   --zIndex-interactiveCanvas: 2;
+  --zIndex-svgLayer: 3;
   --zIndex-wysiwyg: 3;
   --zIndex-canvasButtons: 3;
   --zIndex-layerUI: 4;