CSS fix of roster height.

Illustrated via tests.

css/converse.css

@@ -887,7 +887,7 @@ dl.add-converse-contact {
   position: relative;
   margin: 0.5em 0 0 0;
   height: 194px;
-  height: calc(100% - 25px);
+  height: calc(100% - 68px);
   overflow-x: hidden;
 }
 #converse-roster .roster-filter {
@@ -917,7 +917,7 @@ dl.add-converse-contact {
   overflow-y: auto;
   overflow-x: hidden;
   max-height: 195px;
-  max-height: calc(100% - 67px);
+  max-height: calc(100% - 26px);
 }
 #converse-roster .group-toggle {
   color: #666;

less/converse.less

@@ -985,7 +985,7 @@ dl.add-converse-contact {
     position: relative;
     margin: 0.5em 0 0 0;
     height: 194px;
-    height: ~"calc(100% - 25px)";
+    height: ~"calc(100% - 68px)";
     overflow-x: hidden;
 }
 
@@ -1020,7 +1020,7 @@ dl.add-converse-contact {
     overflow-y: auto;
     overflow-x: hidden;
     max-height: 195px;
-    max-height: ~"calc(100% - 67px)";
+    max-height: ~"calc(100% - 26px)";
 }
 
 #converse-roster .group-toggle {