Correct logic of getting assembly_id
Correct logic of getting assembly_id

Seems that sometimes ensembl splits the assembly id onto multiple lines.
When this happens we do not correctly extract the assembly id. So we
join the assemblies when it looks like they have been split.

RNAcentral/rnacentral-import-pipeline,RNAcentral/rnacentral-import-pipeline,RNAcentral/rnacentral-import-pipeline,RNAcentral/rnacentral-import-pipeline