In #34021 the ngtsc compiler gained the ability to emit type parameter
constraints, which would generate imports for any type reference that
is used within the constraint. However, the `AbsoluteModuleStrategy`
reference emitter strategy did not consider interface declarations as a
valid declaration it can generate an import for, throwing an error
instead.
This commit fixes the issue by including interface declarations in the
logic that determines whether something is a declaration.
Fixes#34837
PR Close#34849
6ddf5508db