handle W/m2 unit and extend test with more accurate CRD test

[Nospamas]

Hopefully removes errors from deserializing / normalizing stage related to the conversion of the W/m^2 unit type.

Tested via running an insert on todays crd data into the new test database via my local machine. No errors appeared in the logs and we inserted approx 3.3k of these observations under this variable.

For convenience this query will pull out the observations:

select o.*
from meta_vars v
inner join meta_network n on v.network_id = n.network_id
inner join obs_raw o on v.vars_id = o.vars_id
where n.network_id = 36 AND v.vars_id = 744 AND o.mod_time between '2025-12-16 00:00:00' and '2025-12-16 23:59:59'

[jameshiebert]

LGTM!