Explore - Need more group.by options for release

### Problem Statement

Currently the release group by option is grouping releases by the actual full "object".
With mobile projects where multiple release could have different adoption at the same time this becomes a difficult problem.

For example:
Release A - Package A
Release A - Package B
Release A - Package C
Will already create 3 different group_by rows in explore

There is no way currently to surface how the release in general is doing from different packages

### Solution Brainstorm

Need to be able to group_by by release.name or at least the string value of the release instead of the whole object.

### Product Area

Unknown

Start by locating the Explore implementation for release group_by handling and its existing tests. Compare grouping by the full release object with grouping by release.name or its string value, then add coverage showing that releases sharing a name are combined while distinct releases remain separate.

Written by the indexing model from the issue text.