Per context visualizations need better title/documentation

[MahmoodEtedadi]

Problem Summary

In some visualizations (e.g., sm.ExploreModelEvaluation()) with combine scores? selected, the title of visualization is Per Encounter.

1. The title should change to Per Context.
2. Documentation should be updated to clarify that with combine scores, scores are combined considering the combination of entity_id, context_id from usage_config.yml.

As an enhancement, for show_cohort_summaries:
3. Documentation should be updated to clarify that Entities are the counts after grouping by only entity_id.
4. Maybe add another Contexts column that computes number of contexts after grouping by both entity_id, context_id (so Contexts should always be greater than or equal to Entities).

Impact

Might cause confusion.

Possible Solution

Steps to Reproduce

Suggested fix