Issue Summary

I was not able to publish article in Confluence (on Hello). Article was created with old-style template

I think other customers may experience similar problem as well? I think there are 2 areas to address here
1) Ideally, localStorage should be used as little as possible, not to get over quota. Another way may be to delete most old keys and their data from localStorage (if it is feasible for this type of data)?
2) even if this thing cannot be saved to localStorage, user should be still able to Publish article

Steps to Reproduce

1. Fill in localStorage for confluence website with some clutter (example of code is here https://stackoverflow.com/a/46730251/1343917) 
2. Try to create and publish an article (click "Publish" button). I used old-style template for this, not sure if it matters.

Expected Results

Article is saved 

Actual Results

Article is not saved

The below exception is thrown in the browser console

```
Uncaught DOMException: Failed to execute 'setItem' on 'Storage': Setting the value of 'localStorage/atlassian.5adfcc8b424d6b2e29a06c61.frontend.editor.tinyMCE.just.published' exceeded the quota.
```

Workaround

When I cleared localStorage - I was able to Publish the article.