stream_list_sort: Remove unused function.

This function was introduced in c1b5021d84
but was never used.

(cherry picked from commit 87864992a8)

web/src/stream_list_sort.ts

@@ -57,10 +57,6 @@ export function is_filtering_inactives(): boolean {
     return filter_out_inactives;
 }
 
-export function has_recent_activity_but_muted(sub: StreamSubscription): boolean {
-    return sub.is_recently_active && sub.is_muted;
-}
-
 type StreamListSortResult = {
     same_as_before: boolean;
     pinned_streams: number[];

web/tests/stream_list_sort.test.cjs

@@ -201,18 +201,6 @@ test("basics", () => {
     assert.deepEqual(sorted.dormant_streams, []);
 });
 
-test("has_recent_activity_but_muted", () => {
-    const sub = {
-        name: "cats",
-        subscribed: true,
-        stream_id: 111,
-        is_muted: true,
-        is_recently_active: true,
-    };
-    stream_data.add_sub(sub);
-    assert.ok(stream_list_sort.has_recent_activity_but_muted(sub));
-});
-
 test("filter inactives", ({override}) => {
     override(
         user_settings,