…lass (#14721)

In v8, types have been exported from `@sentry/types`, while
implementations have been exported from other classes.
This lead to some duplication, where we had to keep an interface in
`@sentry/types`, while the implementation mirroring that interface was
kept e.g. in `@sentry/core`.
Since in v9 the types have been merged into `@sentry/core`, we can get
rid of some of this duplication. This means that certain things that
used to be a separate interface, will not expect an actual instance of
the class/concrete implementation. This should not affect most users,
unless you relied on passing things with a similar shape to internal
methods.

This PR removes the `Scope` interface, in favor of just using the scope
class everywhere.

This is related to
#9840

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Co-authored-by: Sigrid Huemer <[email protected]>