fix(avatar) refactor preloading to avoid CORS issues

Fixes: https://github.com/jitsi/jitsi-meet/issues/8510

This basically reverts
a3fb996ff0
while retaining the same properties that prompted it's original intent, namely
avoiding sending the Referrer header.

react/features/base/participants/preloadImage.web.js

@@ -15,16 +15,13 @@ export function preloadImage(src: string | Object): Promise<string> {
     }
 
     return new Promise((resolve, reject) => {
-        fetch(src, { referrer: '' })
-            .then(response => {
-                if (response.ok) {
-                    resolve(src);
-                } else {
-                    reject();
-                }
-            })
-            .catch(e => {
-                reject(e);
-            });
+        const image = document.createElement('img');
+
+        image.onload = () => resolve(src);
+        image.onerror = reject;
+
+        // $FlowExpectedError
+        image.referrerPolicy = 'no-referrer';
+        image.src = src;
     });
 }