Fix importing trees with utf8 characters

[alesan99]

Fixes #7778

Databases with a latin1 character set will crash when importing trees with certain UTF-8 characters (Like the Minerals tree).
This PR prevents the crash, but the taxon names inside the Minerals tree still doesn't show up 100% correct simply because the database does not support it.

Checklist

• Self-review the PR after opening it to make sure the changes look good and
  self-explanatory (or properly documented)
• Add relevant issue to release milestone
• Add pr to documentation list
• Add automated tests
• Add a reverse migration if a migration is present in the PR

Testing instructions

• Go to the Taxon tree viewer
• Import a new tree, choose Minerals
• See that the tree imported correctly, without errors.
• If you are using an existing database (not one created with the guided setup), no Taxon names should be garbled (like in the screenshot here -> New tree from Minerals default has incorrect encoding #7778)
• Try to import other trees to make sure they still work.