fix: update dimensions for embeddable elements in default_canvas.json

- Increased width from 420 to 460 and height from 320 to 380 for improved layout of embeddable elements.

Author: atyrode

src/backend/default_canvas.json

@@ -2154,8 +2154,8 @@
             "type": "embeddable",
             "angle": 0,
             "index": "b0q",
-            "width": 420,
-            "height": 320,
+            "width": 460,
+            "height": 380,
             "locked": false,
             "frameId": null,
             "opacity": 100,