Fix #30968: Lightmap Pack - no new image limit

Disable operator register and redo flags because it might modify non-mesh
data when in edit mode. This doesn't work properly with current undo stack
design.

release/scripts/startup/bl_operators/uvcalc_lightmap.py

@@ -549,7 +549,6 @@ class LightMapPack(Operator):
     '''Follow UVs from active quads along continuous face loops'''
     bl_idname = "uv.lightmap_pack"
     bl_label = "Lightmap Pack"
-    bl_options = {'REGISTER', 'UNDO'}
 
     PREF_CONTEXT = bpy.props.EnumProperty(
             name="Selection",