DOI: Passing a malfomed DOI doesn't show the error

[fenekku]

Package version (if known): v6.0

Describe the bug

Entering a malformed DOI doesn't show the error (but there is an error banner at least).

Steps to Reproduce

1. Save a new record with a malformed DOI
2. See the error banner is shown

Expected behavior

Show the DOI specific error.

Screenshots (if applicable)

After saving the record with the malformed DOI (DOI: blablbalb blabl)

[fenekku]

As of v8

The banner now has: DOI: Invalid DOI and the erroneous DOI is kept in the field, but the field is still not highlighted in red.