Sculpt: Improve Set Pivot Position UI

- Don't show the "Mouse X" and "Mouse Y" properties in the redo panel
  for all the modes that don't use them.
- Use the recently added dynamic version of the "depends on cursor"
  setting to only wait for mouse click for the "cursor surface" mode.

Arguably these should be different operators anyway.

source/blender/editors/sculpt_paint/sculpt_transform.cc

@@ -370,6 +370,15 @@ static EnumPropertyItem prop_sculpt_pivot_position_types[] = {
     {0, nullptr, 0, nullptr, nullptr},
 };
 
+static bool set_pivot_depends_on_cursor(bContext & /*C*/, wmOperatorType & /*ot*/, PointerRNA *ptr)
+{
+  if (!ptr) {
+    return true;
+  }
+  const PivotPositionMode mode = PivotPositionMode(RNA_enum_get(ptr, "mode"));
+  return mode == PivotPositionMode::CursorSurface;
+}
+
 static int set_pivot_position_exec(bContext *C, wmOperator *op)
 {
   Object &ob = *CTX_data_active_object(C);
@@ -474,6 +483,17 @@ static int set_pivot_position_invoke(bContext *C, wmOperator *op, const wmEvent
   return set_pivot_position_exec(C, op);
 }
 
+static bool set_pivot_position_poll_property(const bContext * /*C*/,
+                                             wmOperator *op,
+                                             const PropertyRNA *prop)
+{
+  if (STRPREFIX(RNA_property_identifier(prop), "mouse_")) {
+    const PivotPositionMode mode = PivotPositionMode(RNA_enum_get(op->ptr, "mode"));
+    return mode == PivotPositionMode::CursorSurface;
+  }
+  return true;
+}
+
 void SCULPT_OT_set_pivot_position(wmOperatorType *ot)
 {
   ot->name = "Set Pivot Position";
@@ -483,8 +503,10 @@ void SCULPT_OT_set_pivot_position(wmOperatorType *ot)
   ot->invoke = set_pivot_position_invoke;
   ot->exec = set_pivot_position_exec;
   ot->poll = SCULPT_mode_poll;
+  ot->depends_on_cursor = set_pivot_depends_on_cursor;
+  ot->poll_property = set_pivot_position_poll_property;
 
-  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO | OPTYPE_DEPENDS_ON_CURSOR;
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
   RNA_def_enum(ot->srna,
                "mode",
                prop_sculpt_pivot_position_types,