Gui: Fix Std_LinkActions

Currently the active button of the Std_LinkActions command is toggable that is confusing behaviour.
This PR makes the action group non-checkable

src/Gui/CommandLink.cpp

@@ -882,6 +882,8 @@ public:
         eType         = AlterDoc;
         bCanLog       = false;
 
+        setCheckable(false);
+
         addCommand(new StdCmdLinkMake());
         addCommand(new StdCmdLinkMakeRelative());
         addCommand(new StdCmdLinkReplace());