Use button tag instead of anchor in sequence + remove duplicated css

refs #2693

app/Resources/public/css/base.css

@@ -5425,16 +5425,6 @@ div#chat-remote-video video {
     font-size: 12px;
 }
 
-#parents .parent .big-icon .sequence-id {
-    border-radius: 50%;
-    background-color: #E74C3C;
-    width: 20%;
-    color: #ffffff;
-    position: absolute;
-    right: 5px;
-    top: 5px;
-}
-
 #parents .parent .big-icon .sequence-deleted {
     font-size: 12px;
 }
@@ -5463,16 +5453,6 @@ div#chat-remote-video video {
     font-size: 12px;
 }
 
-#resource .parent .big-icon .sequence-id {
-    border-radius: 50%;
-    background-color: #E74C3C;
-    width: 20%;
-    color: #ffffff;
-    position: absolute;
-    right: 5px;
-    top: 5px;
-}
-
 #resource .parent .big-icon .sequence-deleted {
     font-size: 12px;
 }
@@ -5509,7 +5489,10 @@ div#chat-remote-video video {
     font-size: 12px;
 }
 
+#parents .parent .big-icon .sequence-id,
+#resource .parent .big-icon .sequence-id,
 #children .parent .big-icon .sequence-id {
+    border: 0 none;
     border-radius: 50%;
     background-color: #E74C3C;
     width: 20%;

main/inc/ajax/sequence.ajax.php

@@ -94,7 +94,7 @@ switch ($action) {
                     $link .= '<div class="big-icon">';
                     $link .= $image;
                     $link .= '<div class="sequence-course">'.$sessionInfo['name'].'</div>';
-                    $link .= '<a href="#" class="sequence-id">'.$id.'</a>';
+                    $link .= '<button type="button" class="sequence-id">'.$id.'</button>';
                     $link .= $linkDelete;
                     $link .= $linkUndo;
                     $link .= '</div></div>';