people: Add `version` parameter for medium sized avatar urls.

We need to append the `version` parameter when constructing the urls for
medium-sized images so that the browser updates the image in real time when
the user uploads a new avatar.

Fixes #25558.

web/src/people.js

@@ -736,7 +736,14 @@ export function medium_avatar_url_for_person(person) {
         return medium_gravatar_url_for_email(person.email);
     }
 
-    return "/avatar/" + person.user_id + "/medium";
+    // We need to attach a version to the URL as a cache-breaker so that the browser
+    // will update the image in real time when user uploads a new avatar.
+    //
+    // TODO: Newly created users sometimes are first learned about via
+    // the report_late_add code path; these are missing the avatar_version
+    // metadata. Long term, we should clean up that possibility, but
+    // until it is, we fallback to using a version number of 0.
+    return `/avatar/${person.user_id}/medium?version=${person.avatar_version ?? 0}`;
 }
 
 export function sender_info_for_recent_topics_row(sender_ids) {

web/tests/people.test.js

@@ -746,8 +746,8 @@ test_people("message_methods", () => {
         people.medium_avatar_url_for_person(maria),
         "https://secure.gravatar.com/avatar/6dbdd7946b58d8b11351fcb27e5cdd55?d=identicon&s=500",
     );
-    assert.equal(people.medium_avatar_url_for_person(charles), "/avatar/301/medium");
-    assert.equal(people.medium_avatar_url_for_person(ashton), "/avatar/303/medium");
+    assert.equal(people.medium_avatar_url_for_person(charles), "/avatar/301/medium?version=0");
+    assert.equal(people.medium_avatar_url_for_person(ashton), "/avatar/303/medium?version=0");
 
     muted_users.add_muted_user(30);
     assert.deepEqual(people.sender_info_for_recent_topics_row([30]), [

web/tests/popovers.test.js

@@ -206,7 +206,7 @@ test_ui("sender_hover", ({override, mock_template}) => {
     handler.call($target, e);
 
     const avatar_img = image_stubber.get(0);
-    assert.equal(avatar_img.src.toString(), "/avatar/42/medium");
+    assert.equal(avatar_img.src.toString(), "/avatar/42/medium?version=5");
 
     // todo: load image
 });