Revert "Member avatars without canvas" (#10057

* Revert "Apply more general fix for base avatar regressions (#10045)"

This reverts commit 371a3c0d36.

* Revert "Fix layout and visual regressions around default avatars (#10031)"

This reverts commit 0d1fce37b2.

* Revert "Member avatars without canvas (#9990)"

This reverts commit a8aa4de4b4.

* Update snapshots

test/components/structures/__snapshots__/UserMenu-test.tsx.snap

@@ -20,16 +20,22 @@ exports[`<UserMenu> when rendered should render as expected 1`] = `
         <span
           class="mx_BaseAvatar mx_UserMenu_userAvatar_BaseAvatar"
           role="presentation"
-          style="width: 32px; height: 32px;"
         >
           <span
             aria-hidden="true"
-            class="mx_BaseAvatar_image mx_BaseAvatar_initial"
-            data-testid="avatar-img"
-            style="background-color: rgb(54, 139, 214); width: 32px; height: 32px; font-size: 20.8px; line-height: 32px;"
+            class="mx_BaseAvatar_initial"
+            style="font-size: 20.8px; width: 32px; line-height: 32px;"
           >
             U
           </span>
+          <img
+            alt=""
+            aria-hidden="true"
+            class="mx_BaseAvatar_image"
+            data-testid="avatar-img"
+            src="data:image/png;base64,00"
+            style="width: 32px; height: 32px;"
+          />
         </span>
       </div>
     </div>