streams: Correctly disable adding subscribers while creating streams.

This commit disables the field used for adding other subscribers
in stream creation box for users who are not allowed to add
other users to streams because of realm level setting
"Who can add users to  streams".

Fixes #24900.

web/src/stream_create.js

@@ -15,6 +15,7 @@ import * as settings_data from "./settings_data";
 import * as stream_create_subscribers from "./stream_create_subscribers";
 import * as stream_data from "./stream_data";
 import * as stream_settings_ui from "./stream_settings_ui";
+import * as stream_ui_updates from "./stream_ui_updates";
 import * as ui_report from "./ui_report";
 import {parse_html} from "./ui_util";
 
@@ -360,6 +361,15 @@ export function show_new_stream_modal() {
             });
         }
     }
+    const $add_subscribers_container = $(
+        "#stream_creation_form .subscriber_list_settings",
+    ).expectOne();
+
+    stream_ui_updates.enable_or_disable_add_subscribers_elements(
+        $add_subscribers_container,
+        settings_data.user_can_subscribe_other_users(),
+        true,
+    );
 
     // set default state for "announce stream" option.
     update_announce_stream_state();