Add fallback of contentType for a fileType value

[Jonesy]

Description

Some file uploads lose their filetype value post upload. This PR has a fallback if there is no filetype it will either try and show the content-type or unknown if nothing exists on the metadata for the file.

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

[jujaga]

Looks good to me.