popovers.js: Add version to user avatar request.

When a user changes its avatar image, the user's avatar in popovers
wasn't being correctly updated, because of browser caching of the
avatar image.  We added a version on the request to get the image in
the same format we use elsewhere, so the browser knows when to use the
cached image or to make a new request to the server.

Edited by Tim to preserve/fix sort orders in some tests, and update
zulip_feature_level.

Fixes: #14290

frontend_tests/node_tests/popovers.js

@@ -50,6 +50,7 @@ const alice = {
     email: 'alice@example.com',
     full_name: 'Alice Smith',
     user_id: 42,
+    avatar_version: 5,
     is_guest: false,
     is_admin: false,
 };
@@ -184,13 +185,16 @@ run_test('sender_hover', () => {
     });
 
     $('.user_popover_email').each = noop;
-
     const image_stubber = make_image_stubber();
-
+    window.location = {
+        href: 'http://chat.zulip.org/',
+    };
+    const base_url = window.location.href;
     handler.call(target, e);
 
     const avatar_img = image_stubber.get(0);
-    assert.equal(avatar_img.src, 'avatar/42/medium');
+    const expected_url = new URL('avatar/42/medium?v=' + alice.avatar_version, base_url);
+    assert.equal(avatar_img.src.toString(), expected_url.toString());
 
     // todo: load image
 });