don't open right panel when switching room again

a view_right_panel_phase is dispatched by RoomHeaderButtons
on view_room, which was triggering this to show the panel again.

Check the fromHeader flag just like when hiding the panel so
only room header buttons can hide or show the right panel

src/components/views/right_panel/HeaderButtons.js

@@ -59,7 +59,7 @@ export default class HeaderButtons extends React.Component {
                     phase: null,
                 });
             } else {
-                if (this.props.collapsedRhs) {
+                if (this.props.collapsedRhs && payload.fromHeader) {
                     dis.dispatch({
                         action: 'show_right_panel',
                     });