misc: fix dispatching actions twice when mapDispatchToProps is used

The functions need not return anything, or it will be dispatched as another
action.

react/features/conference/components/Conference.native.js

          * @private
          */
         _onConnect() {
-            return dispatch(connect());
+            dispatch(connect());
         },
 
         /**
          * @private
          */
         _onDisconnect() {
-            return dispatch(disconnect());
+            dispatch(disconnect());
         },
 
         /**
          * @private
          */
         _setToolboxVisible(visible: boolean) {
-            return dispatch(setToolboxVisible(visible));
+            dispatch(setToolboxVisible(visible));
         }
     };
 }

react/features/overlay/components/ReloadButton.js

          * @returns {Object} Dispatched action.
          */
         _reloadNow() {
-            return dispatch(_reloadNow());
+            dispatch(_reloadNow());
         }
     };
 }

react/features/toolbox/components/SecondaryToolbar.web.js

          * @returns {Object} Dispatched action.
          */
         _onSideToolbarContainerToggled(containerId: string) {
-            return dispatch(toggleSideToolbarContainer(containerId));
+            dispatch(toggleSideToolbarContainer(containerId));
         }
     };
 }

react/features/toolbox/components/Toolbox.native.js

          * @type {Function}
          */
         _onRoomLock() {
-            return dispatch(beginRoomLockRequest());
+            dispatch(beginRoomLockRequest());
         },
 
         /**
          * @type {Function}
          */
         _onShareRoom() {
-            return dispatch(beginShareRoom());
+            dispatch(beginShareRoom());
         },
 
         /**
          * @type {Function}
          */
         _onToggleAudioOnly() {
-            return dispatch(toggleAudioOnly());
+            dispatch(toggleAudioOnly());
         },
 
         /**
          * @type {Function}
          */
         _onToggleCameraFacingMode() {
-            return dispatch(toggleCameraFacingMode());
+            dispatch(toggleCameraFacingMode());
         }
     };
 }

react/features/toolbox/functions.native.js

             // business to know that anyway. The undefined value is our
             // expression of (1) the lack of knowledge & (2) the desire to no
             // longer have a valid room name to join.
-            return dispatch(appNavigate(undefined));
+            dispatch(appNavigate(undefined));
         },
 
         /**
          * @type {Function}
          */
         _onToggleAudio() {
-            return dispatch(toggleAudioMuted());
+            dispatch(toggleAudioMuted());
         },
 
         /**
          * @type {Function}
          */
         _onToggleVideo() {
-            return dispatch(toggleVideoMuted());
+            dispatch(toggleVideoMuted());
         }
     };
 }