fix: correct essentials category for Canny node

Amp-Thread-ID: https://ampcode.com/threads/T-019c7303-ab53-7341-be76-a5da1f7a657e
Co-authored-by: Amp <amp@ampcode.com>

Author: Yourz

comfy_extras/nodes_canny.py

@@ -12,7 +12,7 @@ def define_schema(cls):
             node_id="Canny",
             search_aliases=["edge detection", "outline", "contour detection", "line art"],
             category="image/preprocessors",
-            essentials_category="Image Tools/Preprocessing",
+            essentials_category="Image Tools",
             inputs=[
                 io.Image.Input("image"),
                 io.Float.Input("low_threshold", default=0.4, min=0.01, max=0.99, step=0.01),