Remove flex utilities from .list-group-item's as they're display: block;...

Remove flex utilities from .list-group-item's as they're display: block; meaning the utilities have no affect. Closes #27162.

site/docs/4.1/components/list-group.md

@@ -156,7 +156,7 @@ Add nearly any HTML within, even for linked list groups like the one below, with
 
 {% capture example %}
 <div class="list-group">
-  <a href="#" class="list-group-item list-group-item-action flex-column align-items-start active">
+  <a href="#" class="list-group-item list-group-item-action active">
     <div class="d-flex w-100 justify-content-between">
       <h5 class="mb-1">List group item heading</h5>
       <small>3 days ago</small>
@@ -164,7 +164,7 @@ Add nearly any HTML within, even for linked list groups like the one below, with
     <p class="mb-1">Donec id elit non mi porta gravida at eget metus. Maecenas sed diam eget risus varius blandit.</p>
     <small>Donec id elit non mi porta.</small>
   </a>
-  <a href="#" class="list-group-item list-group-item-action flex-column align-items-start">
+  <a href="#" class="list-group-item list-group-item-action">
     <div class="d-flex w-100 justify-content-between">
       <h5 class="mb-1">List group item heading</h5>
       <small class="text-muted">3 days ago</small>
@@ -172,7 +172,7 @@ Add nearly any HTML within, even for linked list groups like the one below, with
     <p class="mb-1">Donec id elit non mi porta gravida at eget metus. Maecenas sed diam eget risus varius blandit.</p>
     <small class="text-muted">Donec id elit non mi porta.</small>
   </a>
-  <a href="#" class="list-group-item list-group-item-action flex-column align-items-start">
+  <a href="#" class="list-group-item list-group-item-action">
     <div class="d-flex w-100 justify-content-between">
       <h5 class="mb-1">List group item heading</h5>
       <small class="text-muted">3 days ago</small>