fix: check JENKINS_URL before HUDSON_URL

[gperdomor]

This PR resolves #170...

[pi0]

Thanks!

Ref for future: https://github.com/jenkinsci/jenkins/blob/422e3b8990be73796a8381fa86f982ce5c1f9da4/core/src/main/java/jenkins/model/CoreEnvironmentContributor.java#L49

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.51%. Comparing base (5558f03) to head (b9138e8).
⚠️ Report is 37 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #171      +/-   ##
==========================================
- Coverage   82.08%   73.51%   -8.57%     
==========================================
  Files          10       10              
  Lines         374      219     -155     
  Branches       33       31       -2     
==========================================
- Hits          307      161     -146     
+ Misses         61       53       -8     
+ Partials        6        5       -1     

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