datacite payload should be saved to curation log even when minting fails

[only1chunts]

User story

As a curator
I want the XML payload generated for minting the DOI to be saved
So that I can audit it easily even when the minting fails

Acceptance criteria

Given I click the Mint DOI button on the dataset admin page
When the XML payload is created
Then it is saved and linked to from the curators log, even if the minting is not successful

Additional Info

Currently the work in #372 is only saving the successfully minted DOI payloads, which means when it fails we cant see what was in the XML which would be very useful to help trouble shoot what went wrong.

Product Backlog Item Ready Checklist

• Business value is clearly articulated
• Item is understood enough by the IT team so it can make an informed decision as to whether it can complete this item
• Dependencies are identified and no external dependencies would block this item from being completed
• At the time of the scheduled sprint, the IT team has the appropriate composition to complete this item
• This item is estimated and small enough to comfortably be completed in one sprint
• Acceptance criteria are clear and testable
• Performance criteria, if any, are defined and testable
• The Scrum team understands how to demonstrate this item at the sprint review

Product Backlog Item Done Checklist

• Item(s) in increment pass all Acceptance Criteria
• Code is refactored to best practices and coding standards
• Documentation is updated as needed
• Data security has not been compromised (with particular reference to the personal information we hold in GigaDB)
• No deviation from the team technology stack and software architecture has been introduced
• The product is in a releasable state (i.e. the increment has not broken anything)