fix(copy): add support for copying `Blob` objects

Although `copy()` does not need to (and never will) support all kinds of objects, there is a
(not uncommon) usecase for supporting `Blob` objects:

`ngMock`'s `$httpBackend` will return a copy of the response data (so that changes in one test won't
affect others). Since returning `Blob` objects in response to HTTP requests is a valid usecase and
since `ngMocks`'s `$httpBackend` will use `copy()` to create a copy of that data, it is reasonable
to support `Blob` objects.
(I didn't run any benchmarks, but the additional check for the type of the copied element should
have negligible impact, compared to the other stuff that `copy()` is doing.)

Fixes #9669

Closes #14064