Settings: Siminfo: Include .separator CSS

Bug: 788148
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I82a5d1ca789d62effc897ccccd981dc12c93610b
Reviewed-on: https://chromium-review.googlesource.com/804236Reviewed-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521112}

ui/webui/resources/cr_components/chromeos/network/network_siminfo.html

@@ -41,6 +41,14 @@
         min-width: 200px;
       }
 
+      .separator {
+        -webkit-border-start: var(--cr-separator-line);
+        -webkit-margin-end: var(--cr-section-padding);
+        -webkit-margin-start: var(--cr-section-padding);
+        flex-shrink: 0;
+        height: calc(var(--cr-section-min-height) - 9px);
+      }
+
       paper-toggle-button {
         -webkit-margin-start: var(--cr-button-edge-spacing);
       }