PLT-6689: fix user image requests (#6946)

* fix user image requests

* fix eslint errors and a few more cache busters

webapp/components/webrtc/components/webrtc_notification.jsx

@@ -1,7 +1,6 @@
 // Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
-import {Client4} from 'mattermost-redux/client';
 import WebSocketClient from 'client/web_websocket_client.jsx';
 
 import UserStore from 'stores/user_store.jsx';
@@ -197,7 +196,7 @@ export default class WebrtcNotification extends React.Component {
         const user = this.state.userCalling;
         if (user) {
             const username = Utils.displayUsername(user.id);
-            const profileImgSrc = Client4.getUsersRoute() + '/' + user.id + '/image?time=' + (user.last_picture_update || new Date().getTime());
+            const profileImgSrc = Utils.imageURLForUser(user);
             const profileImg = (
                 <img
                     className='user-popover__image'

webapp/components/webrtc/webrtc_controller.jsx

@@ -5,7 +5,6 @@ import UserStore from 'stores/user_store.jsx';
 import ChannelStore from 'stores/channel_store.jsx';
 import WebrtcStore from 'stores/webrtc_store.jsx';
 
-import {Client4} from 'mattermost-redux/client';
 import WebSocketClient from 'client/web_websocket_client.jsx';
 import Janus from 'janus';
 
@@ -84,14 +83,14 @@ export default class WebrtcController extends React.Component {
 
         const currentUser = UserStore.getCurrentUser();
         const remoteUser = UserStore.getProfile(props.userId);
-        const remoteUserImage = Client4.getUsersRoute() + '/' + remoteUser.id + '/image?time=' + remoteUser.last_picture_update;
+        const remoteUserImage = Utils.imageURLForUser(remoteUser);
 
         this.state = {
             windowWidth: Utils.windowWidth(),
             windowHeight: Utils.windowHeight(),
             channelId: ChannelStore.getCurrentId(),
             currentUser,
-            currentUserImage: Client4.getUsersRoute() + '/' + currentUser.id + '/image?time=' + currentUser.last_picture_update,
+            currentUserImage: Utils.imageURLForUser(currentUser),
             remoteUserImage,
             localMediaLoaded: false,
             isPaused: false,
@@ -133,7 +132,7 @@ export default class WebrtcController extends React.Component {
             (nextProps.userId !== this.props.userId) ||
             (nextProps.isCaller !== this.props.isCaller)) {
             const remoteUser = UserStore.getProfile(nextProps.userId);
-            const remoteUserImage = Client4.getUsersRoute() + '/' + remoteUser.id + '/image?time=' + remoteUser.last_picture_update;
+            const remoteUserImage = Utils.imageURLForUser(remoteUser);
             this.setState({
                 error: null,
                 remoteUserImage