message_feed: Remove separate Subscribe/Unsubscribe buttons.

This removes Subscribe/Unsubscribe buttons in trailing bookends,
including the can_toggle_subscription plumbing supporting them.

Fixes #32125.

web/src/message_list.ts

@@ -430,8 +430,6 @@ export class MessageList {
         const subscribed = stream_data.is_subscribed(stream_id);
         const invite_only = sub?.invite_only;
         const is_web_public = sub?.is_web_public;
-        const can_toggle_subscription =
-            sub !== undefined && stream_data.can_toggle_subscription(sub);
         if (sub === undefined || sub.is_archived) {
             deactivated = true;
         } else if (!subscribed && !this.last_message_historical) {
@@ -443,7 +441,6 @@ export class MessageList {
             subscribed,
             deactivated,
             just_unsubscribed,
-            can_toggle_subscription,
             page_params.is_spectator,
             invite_only ?? false,
             is_web_public ?? false,

web/src/message_list_view.ts

@@ -1953,7 +1953,6 @@ export class MessageListView {
         subscribed: boolean,
         deactivated: boolean,
         just_unsubscribed: boolean,
-        can_toggle_subscription: boolean,
         is_spectator: boolean,
         invite_only: boolean,
         is_web_public: boolean,
@@ -1963,7 +1962,6 @@ export class MessageListView {
         const $rendered_trailing_bookend = $(
             render_bookend({
                 stream_name,
-                can_toggle_subscription,
                 subscribed,
                 deactivated,
                 just_unsubscribed,

web/templates/bookend.hbs

@@ -26,15 +26,4 @@
             {{/if}}
         </span>
     {{/if}}
-    {{#if can_toggle_subscription}}
-    <div class="sub_button_row">
-        <button class="button white rounded stream_sub_unsub_button {{#unless subscribed}}sea-green{{/unless}}" type="button" name="subscription">
-            {{#if subscribed}}
-            {{t 'Unsubscribe' }}
-            {{else}}
-            {{t 'Subscribe' }}
-            {{/if}}
-        </button>
-    </div>
-    {{/if}}
 </div>

web/tests/message_list.test.cjs

@@ -359,7 +359,6 @@ run_test("bookend", ({override}) => {
 
     override(stream_data, "is_subscribed", () => is_subscribed);
     override(stream_data, "get_sub_by_id", () => ({invite_only, name: "IceCream"}));
-    override(stream_data, "can_toggle_subscription", () => true);
 
     {
         const stub = make_stub();