Changed the "Same in all tools" behavior (fix #4007)

Now:
1) If some dynamics are set and the "Same on all tools" box is
unchecked, when we check it, aseprite will copy the active
configuration as shared values.
2) If "Same on all tools" is checked, and we uncheck it, aseprite
will copy shared values to the active tool settings (without touching
other tools), in this way the visible options of the active tool
won't be modified.

src/app/ui/dynamics_popup.cpp

@@ -289,9 +289,6 @@ DynamicsPopup::DynamicsPopup(Delegate* delegate)
       // Save the old dynamics options:
       saveDynamicsPref(!sameInAllTools);
       Preferences::instance().shared.shareDynamics(sameInAllTools);
-      // Load the new dynamics options:
-      loadDynamicsPref(sameInAllTools);
-      refreshVisibility();
     });
   m_dynamics->gradientPlaceholder()->addChild(m_ditheringSel);
   m_dynamics->pressurePlaceholder()->addChild(m_pressureThreshold = new ThresholdSlider);