Update Doctest for precision_recall_curve.py

[theory-in-progress]

• In accordance with the Update of Scikit-Learn with version 1.1.1

Fixes #2850

Description:

• The failure happens with Precision Recall Curve
• This was an issue with scikit-learn which was resolved in their PR - FIX compute precision-recall at 100% recall
  • This was because precision_recall_curve() was not returning the full curve at high recall
  • Read more about the issue here
• This Issue persisted Till now because scikit-learn==1.0.2 was being installed and the change in Precision Recall Curve was in version scikit-learn==1.1.1
• Possible reason why this was happening - Python 3.7 was being used, when that changed and 3.7 was dropped from CI

Changes:

• Updated the Doctests to match with Scikit-Learn

Old DocTest Returns:

Precision [1.0, 1.0, 1.0]
Recall [1.0, 0.5, 0.0]
Thresholds [0.7109, 0.9997]

Updated to New DocTest Returns:

Precision [0.5, 0.6667, 1.0, 1.0, 1.0]
Recall [1.0, 1.0, 1.0, 0.5, 0.0]
Thresholds [0.0474, 0.5987, 0.7109, 0.9997]

Check list:

• New tests are added (if a new feature is added)
• New doc strings: description and/or example code are in RST format
• Documentation is updated (if required)

[vfdev-5]

Thanks a lot @theory-in-progress !