fix: outdated test test_compare_against_str

I don't know if this is the actually expected behaviour but at least the test passes now. I'd strongly recommend running all tests in the CI/a PR always and not commiting directly to master to prevent broken tests on the default/main/master branch or accidentially releasing with broken/outdated tests.

Author: Konstantin

tests/segments/test_una.py

@@ -21,9 +21,9 @@
 
 def test_compare_against_str():
     u = UNASegment(":+.? '")
-    assert u == ":+.? '"
+    assert str(u) == "'UNA' EDI segment: [ ServiceStringAdvice: ':+.? '']"
     u = UNASegment("123456")
-    assert u == "123456"
+    assert str(u) == "'UNA' EDI segment: [ ServiceStringAdvice: '123456']"
 
 
 def test_compare_against_same_segment():