Create new ToolbarButton type for Layout Selector; wire up custom UI; prep for viewportGridService usage

extensions/measurement-tracking/src/index.js

@@ -1,4 +1,3 @@
-import getCommandsModule from './getCommandsModule.js';
 import getContextModule from './getContextModule.js';
 import getPanelModule from './getPanelModule.js';
 import getViewportModule from './getViewportModule.js';
@@ -8,7 +7,6 @@ export default {
    * Only required property. Should be a unique value across all extensions.
    */
   id: 'org.ohif.measurement-tracking',
-  getCommandsModule,
   getContextModule,
   getPanelModule,
   getViewportModule,