inbox: Remove empty space below filters for hidden folders.

Hidden folders occupied space due to bottom margin.

Fixed by moving the margin to elements which have `display: none`
property so that margin is removed.

(cherry picked from commit 39b560e611)

web/styles/inbox.css

@@ -645,11 +645,19 @@
 .inbox-folder-components {
     border-radius: 5px;
     border: 0.5px solid hsl(0deg 0% 0% / 13%);
-    /* 8px at 16px / 1em */
-    margin-bottom: 0.5em;
     overflow: hidden;
 }
 
+.inbox-folder-components
+    .inbox-folder-channel:last-child
+    .inbox-topic-container,
+#inbox-direct-messages-container {
+    .inbox-row:last-child {
+        /* 8px at 16px / 1em */
+        margin-bottom: 0.5em;
+    }
+}
+
 .inbox-folder.inbox-collapsed-state,
 .inbox-folder.hidden_by_filters {
     + .inbox-folder-components {

web/templates/inbox_view/inbox_folder_with_channels.hbs

@@ -11,7 +11,7 @@
     {{#each topics_dict as |key_value_list _index|}}
         {{#each ../streams_dict as |stream_key_value _stream_index|}}
             {{#if (and (eq stream_key_value.[1].folder_id ../../id) (eq stream_key_value.[0] key_value_list.[0]))}}
-            <div id="{{key_value_list.[0]}}">
+            <div id="{{key_value_list.[0]}}" class="inbox-folder-channel">
                 {{> inbox_row stream_key_value.[1]}}
                 <div class="inbox-topic-container">
                     {{#each key_value_list.[1]}}