fix display of overlong names on studygroup participants list, fixes #4489

Closes #4489

Merge request studip/studip!3282

resources/assets/stylesheets/scss/studygroup.scss

+#course-studygroup-members {
+    #content h3:first-of-type {
+        margin-top: 0;
+    }
+}
+
 ul.studygroup-gallery {
+    display: flex;
+    flex-direction: row;
+    flex-wrap: wrap;
+    gap: 10px;
     list-style: none;
-    padding-left: 15px;
+    padding-left: 0;
     li {
         box-sizing: border-box;
-        vertical-align: top;
+        display: inline-blocK;
+        flex: 0 0 120px;
+        min-height: 150px;
+        overflow: hidden;
         text-align: center;
-        margin: 5px;
+        vertical-align: top;
         width: 120px;
-        height: 150px;
-        max-height: 150px;
-        overflow: hidden;
-        display: inline-blocK;
-        section {
-            margin: 0 auto;
-
-        }
     }
 }