changed wording on invite existing user selector

static_src/components/users_selector.jsx

@@ -58,8 +58,7 @@ export default class UsersSelector extends React.Component {
     const { parentEntity } = this.props;
     const { currentEntity } = this.props;
 
-    return `Invite an existing user in this ${parentEntity}` +
-      ` to this ${currentEntity}.`;
+    return `Invite an existing ${parentEntity} user to this ${currentEntity}.`;
   }
 
   get userSelector() {

static_src/test/unit/components/users_selector.spec.jsx

@@ -27,7 +27,7 @@ describe('<UsersSelector />', function () {
     });
 
     it('displays proper message', () => {
-      const doc = 'Invite an existing user in this organization to this space.';
+      const doc = 'Invite an existing organization user to this space.';
       expect(wrapper.find(PanelDocumentation).find('p').text()).toBe(doc);
     });
   });