[7.x] Call named scope and consistent method naming

[GrahamCampbell]

1. The model is the source of truth for if a scope exists, but then the builder bypasses it to call the scope method. Instead, we should delegate to the model. This PR addresses this, and provides a reusable way to apply scopes.
2. [7.x] Add hasScope function to the Base Model #32622 added hasScope, but the name hasNamedScope would be more consistent, since callScope expects a full on callable and callNamedScope expects the actual scope name.