GP: Make Layer and Material lists shorter

This reduces UI vertical space.

release/scripts/startup/bl_ui/properties_data_gpencil.py

@@ -128,7 +128,7 @@ class DATA_PT_gpencil_datapanel(Panel):
         row = layout.row()
 
         col = row.column()
-        layer_rows = 8
+        layer_rows = 7
         col.template_list("GPENCIL_UL_layer", "", gpd, "layers", gpd.layers, "active_index", rows=layer_rows)
 
         col = row.column()

release/scripts/startup/bl_ui/properties_material_gpencil.py

@@ -107,7 +107,7 @@ class MATERIAL_PT_gpencil_slots(Panel):
 
         if ob:
             is_sortable = len(ob.material_slots) > 1
-            rows = 8
+            rows = 7
 
             row = layout.row()