on Jira side, search for users by mail, then by name

[dieck]

search_users was looking to a query on the Object of pyclickup.User

the _fetch_pages function will not know how to handle this object, so it will use the string representation: "<pyclickup.User[12345678] 'Firstname Lastname'>", which does not (always) yield proper results.

This change searches first by mail address, which should be quite accurate, then by user name.

Output of variable params in jira.py / search_users()
before:
{'query': <pyclickup.User[12345678] 'Firstname Lastname'>, 'includeActive': True, 'includeInactive': False}

after:
{'query': 'firstname.lastname@domain.tld', 'includeActive': True, 'includeInactive': False}
{'query': 'Firstname Lastname', 'includeActive': True, 'includeInactive': False}

[dieck]

I have not created pull request, but if you merge this, you may want to merge https://github.com/dieck/clickup-to-jira/tree/search_user_with_caching as well, that is Caching for this search version