Index assets on plate_purpose_id and sti_type
[fixes #54187180] Inform user of missing fields
Resolve merge conflict
[fixes #54206094] Add children to PCRR purposes
Merge pull request #785 from JamesGlover/54187180_accession_issues_need_more_informative_error_messages

[fixes #54187180] Inform user of missing fields
Merge pull request #784 from JamesGlover/54206094_pcrr-xp_plates_don't_worl

54206094 pcrr xp plates don't worl