Results 2 issues of Terence Lim

### Context A bug was introduced in https://github.com/iterative/mlem/pull/221, where approach to combining prediction results incorrectly assumed type to be numpy array. This PR utilizes `DatasetAnalyzer` to first determine the type...

bugfix

I was exploring audio transcription on Baseten and attempted the tutorial, and found that these changes had to be made before I could get it working. As referenced from [StubBase](https://docs.baseten.co/reference/sdk/chains#class-truss-chains-stubbase)...