GraphQL: add section id as a filter parameter for EnrollmentsConnection and sectionsConnection objects

[zqian]

Summary:

The GraphQL enrollmentsConnection object only supports the following filter types:

- associatedUserIds
- states
- types

There is NO filter type within the sectionsConnection object.

Expected behavior:

Please add section id and sis_id attributes to both enrollmentsConnection and sectionsConnection objects.

[iamdlfl]

I'd also like to see support for this behavior. Maybe I'm missing it, but there doesn't seem to be a way to get enrollments for a specific section via the GraphQL API.