Errors when ORCID Exporter not called by user

[drn05r]

Event::DataCiteEvent::datacite_doi from the DataCiteDoi plugin appears to call the ORCID::Exporter and generates the following error messages:

Use of uninitialized value in numeric gt (>) at /opt/eprints3/lib/plugins/EPrints/ORCID/Exporter.pm line 444.

[urn:uuid:008637e0-a9b1-49e4-8f2d-6021c93b2baf] Event::DataCiteEvent::datacite_doi: Error during execution: Can't call method "get_value" on an undefined value at /opt/eprints3/lib/plugins/EPrints/ORCID/Exporter.pm line 458.

I believe that based on the current codebase these are the following lines:

orcid_support_advance/lib/plugins/EPrints/ORCID/Exporter.pm

Line 447 in e0b9987

if( $results->{new} > 0)

orcid_support_advance/lib/plugins/EPrints/ORCID/Exporter.pm

Line 461 in e0b9987

$db->save_user_message( $current_user->get_value( "userid" ),

I purpose that for the first issue and the other checks to see whether other indexes in the $results hashref are set should be updated to check they are defined before checking their value. For the second issue just returning immediately if $current_user is not set. In theory this second change negates the specific need for the first change but I think this may still be a good sanity check.