Text of dynamics created via the palette cannot be permanently edited as the edited text is not saved to the score: the text is saved only for dynamics of type DYNAMIC_OTHER.

Fix: If the text of dynamic is changed, the type is also changed to DYNAMIC_OTHER.
fix #21283
fix #12970
fix #20712
Merge pull request #398 from mgavioli/dynamics_editable_text

Dynamics: permanent text edit