[IATI] Org references checks: is/are tense for single/multiple issues found

[stevieflow]

Originally in #1360 (comment)

Checking if the tense is conditional across these tests

Here is a useful example - it looks like some conditional tenses might be in there... but not consistently

https://iati.cove.opendataservices.coop/data/59e04bc8-acce-4722-81de-448d26caf77c

There is 101 organisation ref(s) that are incorrectly formatted:
... seems incorrect

There is 1 organisation ref(s) that can not be found in the publisher list or has a recognised prefix:
.. seems correct

There are 16 publishers from the iati register used in this dataset:
.. seems correct - but we have seen in #1360 that a single issue is described as "are"

I dont know what is set up in CoVE to deal with this and/or whether this is handled specifically to each test, or at all