channel picker keydown enter with no new line (#506)

* Add background color custom css property for people list items

* Update enter keydown logic to prevent new line

* Merge branches

* Merge branches

Author: beth-panx

src/components/mgt-teams-channel-picker/mgt-teams-channel-picker.ts

@@ -713,6 +713,11 @@ export class MgtTeamsChannelPicker extends MgtTemplatedComponent {
   }
 
   private onUserKeyDown(event: KeyboardEvent) {
+    if (event.keyCode === 13) {
+      // No new line
+      event.preventDefault();
+    }
+
     if (this._treeViewState.length === 0) {
       return;
     }