Disable low-sample-count check for non-percentile value

[sjoshi-jpl]

🗒️ Summary

Brief summary of changes if not sufficiently described by commit messages.

⚙️ Test Data and/or Report

One of the following should be included here:

• Reference to regression test included in code (preferred wherever reasonable)
• Attach test data here + outputs of tests

♻️ Related Issues

Fixing ValidationError for Percentiles with low samples