Progress: Pair programming icon - attempt #2

[Erin007]

Follow up to #22878.

The progress tab now shows the pairing icon if a students paired on that level on the detail view of the progress tab.

This PR includes the following changes:

1.) ProgressBubble now has an additional prop pairingIconEnabled (passed in from ProgressBubbleSet from StudentProgressDetailCell that handles whether that ProgressBubble has the potential to show the pairing icon. ProgressBubble Stories have been added to cover these additional scenarios.

2.) ProgressBubble also handles some new logic that determines whether to show the pairing icon based on the aforementioned pairingIconEnabled prop and new information from level.paired

3.) level.paired is an available field on the level passed to the ProgressBubble because we updated levelsWithStatus and levelsByLesson in progressRedux, which are called from sectionProgressRedux

4.) sectionProgressRedux has been updated to include a new function addStudentLevelPairing, which parallels addStudentLevelProgress.

5.) Increased test coverage for sectionProgressRedux

[islemaster]

Looks like we need some whitespace adjustments here. Did we want to put in a more helpful error message if our validation fails?

[islemaster]

🎉 🎉 🎉

[balderdash]

LGTM!