Add error handling for dynamic import in loadCustomGlyphDefinitions

Co-authored-by: Tyriar <2193314+Tyriar@users.noreply.github.com>

Author: Copilot

addons/addon-webgl/src/customGlyphs/CustomGlyphRasterizer.ts

@@ -28,6 +28,10 @@ export function loadCustomGlyphDefinitions(): Promise<void> {
   if (!loadingPromise) {
     loadingPromise = import('./CustomGlyphDefinitions').then(module => {
       customGlyphDefinitions = module.customGlyphDefinitions;
+    }).catch(err => {
+      // Reset the loading promise on failure to allow retry
+      loadingPromise = undefined;
+      throw err;
     });
   }
   return loadingPromise;