Clip Editor: Remove Image label from selector

Unfortunately, it didn't turn out to be as great as I've hoped to it
will.

The issue is: the label eats too much space, making selector buttons
and image name to be barely readable. Initial idea of making the panel
somewhat wider didn't work either: due to the sizing policy of label
it takes a lot of panel width to make image name readable.

release/scripts/startup/bl_ui/space_clip.py

@@ -779,7 +779,7 @@ class CLIP_PT_plane_track(CLIP_PT_tracking_panel, Panel):
         layout.prop(active_track, "name")
         layout.prop(active_track, "use_auto_keying")
         layout.template_ID(
-            active_track, "image", new="image.new", open="image.open", text="Image")
+            active_track, "image", new="image.new", open="image.open")
 
         row = layout.row()
         row.active = active_track.image is not None