Removed cached 'isEditing' state on history stack

[Jonesy]

Description

If user's saved files to a new request and then refreshed, the cached history state of isEditing: true would start the page in edit mode, which would trigger an error as the uploading view of the table doesn't have the request ID to make a proper file request. Now once the edit is complete the state is replaced with isEditing set to false.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Documentation (non-breaking change with enhancements to documentation)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the CONTRIBUTING doc
• I have checked that unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments