[CrOS Cellular] Network item fetch managedProperties if non-empty guid.

Update network-list-item to only fetch managedProperties if its
networkState's guid is non-empty. This call was temporarily wrapped
behind the cellular flag because it was causing OOBE tests to fail.
This was because network-select can contain dummy networks with empty
properties, such as guid.

Bug: 1093185
Change-Id: I864acb0977a92b0e2daed48056caba581b190bf3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2827192
Commit-Queue: Gordon Seto <gordonseto@google.com>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#872912}

ui/webui/resources/cr_components/chromeos/network/network_list_item.js

@@ -261,9 +261,10 @@ Polymer({
       return;
     }
 
-    // Temporarily place fetching managedProperties behind this flag so OOBE
-    // tests pass. TODO(crbug.com/1196507) Remove this check.
-    if (this.isUpdatedCellularUiEnabled_) {
+    // network-list-item supports dummy networkStates that may have an empty
+    // guid, such as those set by network-select. Only fetch managedProperties_
+    // if the network's guid is defined.
+    if (this.networkState.guid) {
       this.networkConfig_.getManagedProperties(this.networkState.guid)
           .then((response) => {
             this.managedProperties_ = response.result;