Fixes collapsed assignees and reviewers sizing

Fixes the collapsed assignees and reviewers
clickable areas caused by some extra margin and padding.

app/assets/javascripts/sidebar/components/assignees/collapsed_assignee_list.vue

@@ -110,7 +110,7 @@ export default {
 <template>
   <div
     v-gl-tooltip="tooltipOptions"
-    :class="{ 'multiple-users': hasMoreThanOneAssignee }"
+    :class="{ 'multiple-users gl-relative': hasMoreThanOneAssignee }"
     :title="tooltipTitle"
     class="sidebar-collapsed-icon sidebar-collapsed-user"
   >

app/assets/javascripts/sidebar/components/reviewers/collapsed_reviewer_list.vue

@@ -89,7 +89,7 @@ export default {
 <template>
   <div
     v-gl-tooltip="tooltipOptions"
-    :class="{ 'multiple-users': hasMoreThanOneReviewer }"
+    :class="{ 'multiple-users gl-relative': hasMoreThanOneReviewer }"
     :title="tooltipTitle"
     class="sidebar-collapsed-icon sidebar-collapsed-user"
   >

app/assets/stylesheets/pages/issuable.scss

@@ -456,12 +456,6 @@
     }
 
     .multiple-users {
-      position: relative;
-      height: 24px;
-      margin-bottom: 17px;
-      margin-top: 4px;
-      padding-bottom: 4px;
-
       .btn-link {
         padding: 0;
         border: 0;