refactor(anta.tests): Nicer result failure messages for AAA test module

[geetanjalimanegslab]

Description

Updated failure messages for following tests

1. test_aaa.py
   • VerifyTacacsServers
   • VerifyTacacsServerGroups
   • VerifyAuthenMethods
   • VerifyAuthzMethods
   • VerifyAcctDefaultMethods
   • VerifyAcctConsoleMethods

Fixes #587

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have run pre-commit for code linting and typing (pre-commit run)
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes (tox -e testenv)

[codspeed-hq]

CodSpeed Performance Report

Merging #1031 will not alter performance

_{Comparing geetanjalimanegslab:issue_587_model_aaa (56e4632) with main (167417a)}

Summary

✅ 22 untouched benchmarks

[carl-baillargeon]

LGTM.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud