convert_otn_erddap_att() results in text representation of a vector when query_worms_common() results in multiple scientific names

[chrisholbrook]

E.g, query_worms_common() returns three scientific names for "blue shark":

> foo <- query_worms_common("blue shark")
[1] "https://www.marinespecies.org/rest/AphiaRecordsByVernacular/blue%20shark"
> foo
[1] "Isurus oxyrinchus" "Lamna nasus"       "Prionace glauca"  

As a result, the internal data object blue_shark_erddapp_att contains some pretty unruly values in Sci.Name column:

> blue_shark_erddap_att$Tag.Metadata$Sci.Name[1]
[1] c("Isurus oxyrinchus", "Lamna nasus", "Prionace glauca")
Levels: c("Isurus oxyrinchus", "Lamna nasus", "Prionace glauca")