Batch Explorer dropping outputFiles when creating task

**Describe the bug**
Parts of JSON pasted in editor gets removed at Add Task view.

I'm trying to create/add task with outputFiles configuration, however it seems like Batch Explorer couldn't parse outputFiles section properly hence removing it.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to 'Jobs' on the left menu
2. Click on a job (in my case, jobtest)
3. Click 'Add task'
4. Click 'JSON editor'
5. Paste task json into editor
6. Switch over to classic form or 'Add and close'
7. Check the task's configuration in JSON mode and see outputFiles section is removed

**Expected behavior**
outputFiles section should be parsed and not removed

**Screenshots**
1. Pasting the task into JSON editor
2. Switch to classic form then back to JSON editor
3. The submitted task

For comparison, here is the same task.json (but with only task ID changed) created via az-cli

**Logs(Click profile > View Logs > app.log, client.log)**
[logs.zip](https://github.com/Azure/BatchExplorer/files/5922912/logs.zip)

**Version (please complete the following information):**
- OS: Windows
- Version 2.8.0-stable.484