[FLINK-2904] [web-dashboard] Fix truncation of task counts when the number is large.

This closes #1321

flink-runtime-web/web-dashboard/app/styles/job.styl

@@ -34,9 +34,8 @@
 .label-group
   .label
     display: inline-block
-    width: 2em
-    padding-left: 0.1em
-    padding-right: 0.1em
+    padding-left: 0.4em
+    padding-right: 0.4em
     margin: 0
     border-right: 1px solid #ffffff
     border-radius(0)

flink-runtime-web/web-dashboard/web/css/index.css

@@ -445,9 +445,8 @@ livechart {
 }
 .label-group .label {
   display: inline-block;
-  width: 2em;
-  padding-left: 0.1em;
-  padding-right: 0.1em;
+  padding-left: 0.4em;
+  padding-right: 0.4em;
   margin: 0;
   border-right: 1px solid #fff;
   -webkit-border-radius: 0;