Check isHidden() when dispatching HTML events to frames

For dockable frames, the component itself is hidden if not the active tab so AWT's `isVisible()` returns false. However
JIDE and the user consider the frame still open, which agrees with `!isHidden()`.

src/main/java/net/rptools/maptool/client/ui/htmlframe/HTMLFrame.java

@@ -310,7 +310,7 @@ public void updateContents(
   /** Run all callback macros for "onChangeSelection". */
   public static void doSelectedChanged() {
     for (HTMLFrame frame : frames.values()) {
-      if (frame.isVisible()) {
+      if (!frame.isHidden()) {
         HTMLPanelContainer.selectedChanged(frame.macroCallbacks);
       }
     }
@@ -319,7 +319,7 @@ public static void doSelectedChanged() {
   /** Run all callback macros for "onChangeImpersonated". */
   public static void doImpersonatedChanged() {
     for (HTMLFrame frame : frames.values()) {
-      if (frame.isVisible()) {
+      if (!frame.isHidden()) {
         HTMLPanelContainer.impersonatedChanged(frame.macroCallbacks);
       }
     }
@@ -333,7 +333,7 @@ public static void doImpersonatedChanged() {
   public static void doTokenChanged(Token token) {
     if (token != null) {
       for (HTMLFrame frame : frames.values()) {
-        if (frame.isVisible()) {
+        if (!frame.isHidden()) {
           HTMLPanelContainer.tokenChanged(token, frame.macroCallbacks);
         }
       }