Fix angle backend detection, though that should no longer be relevant

src/ext/lib/angle-detect/detect-angle-backend.ts

@@ -93,11 +93,16 @@ function detectBackend(str) {
  * @returns
  */
 function detectANGLEBackend(): AngleVersion {
+  try {
     const canvas = document.createElement("canvas");
     const gl = canvas.getContext("webgl2") ||
       canvas.getContext("webgl") ||
       canvas.getContext("experimental-webgl");
 
+    if (!gl) {
+      return AngleVersion.NotAvailable;
+    }
+
     const ext = (gl as any).getExtension("WEBGL_debug_shaders");
 
     if (!ext) {
@@ -126,5 +131,8 @@ function detectANGLEBackend(): AngleVersion {
     const source = ext.getTranslatedShaderSource(shader);
 
     return detectBackend(source);
+  } catch (e) {
+    return AngleVersion.NotAvailable;
+  }
 }