fix: default missing evaluation type in evaluatePlp

[egillax]

Summary

• add a default All evaluation stratum when evaluatePlp() receives predictions without the requested type column
• cover standalone prediction evaluation with a regression test

Fixes #636

Testing

• Rscript -e 'devtools::test(filter = "evaluation")'

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.73%. Comparing base (ea9ba61) to head (918ebac).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #667   +/-   ##
========================================
  Coverage    89.73%   89.73%           
========================================
  Files           49       49           
  Lines        13689    13691    +2     
========================================
+ Hits         12284    12286    +2     
  Misses        1405     1405           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.