Fix #144096: Undo history unknown action on editing curve map

Editing curvemap generates an undo step but with text "unkown action".
This is due to empty name and description on the button. Explictly add
name during button definition, This way `ui_apply_but_undo/ui_apply_but_funcs_after`
uses correct string for undo step.

Pull Request: https://projects.blender.org/blender/blender/pulls/145717

source/blender/editors/interface/templates/interface_template_curve_mapping.cc

@@ -567,8 +567,18 @@ static void curvemap_buttons_layout(uiLayout *layout,
   /* Curve itself. */
   const int size = max_ii(layout->width(), UI_UNIT_X);
   row = &layout->row(false);
-  uiButCurveMapping *curve_but = (uiButCurveMapping *)uiDefBut(
-      block, ButType::Curve, 0, "", 0, 0, size, 8.0f * UI_UNIT_X, cumap, 0.0f, 1.0f, "");
+  uiButCurveMapping *curve_but = (uiButCurveMapping *)uiDefBut(block,
+                                                               ButType::Curve,
+                                                               0,
+                                                               IFACE_("Edit Curve Map"),
+                                                               0,
+                                                               0,
+                                                               size,
+                                                               8.0f * UI_UNIT_X,
+                                                               cumap,
+                                                               0.0f,
+                                                               1.0f,
+                                                               "");
   curve_but->gradient_type = bg;
 
   /* Sliders for selected curve point. */