Fix fetch policy in pipeline editor branch switcher

The typo in the fetch policy leads to several bugs in the branch
switcher of the pipeline editor. This should fix the following bugs:
- branch name in commit form not being updated when user switches
branches
- fetching outdated content even if changes were committed in the branch

Changelog: fixed

app/assets/javascripts/pipeline_editor/pipeline_editor_app.vue

@@ -56,7 +56,7 @@ export default {
 
   apollo: {
     initialCiFileContent: {
-      fetchPolicy: fetchPolicies.NETWORK,
+      fetchPolicy: fetchPolicies.NETWORK_ONLY,
       query: getBlobContent,
       // If it's a brand new file, we don't want to fetch the content.
       // Then when the user commits the first time, the query would run