This is a simplified version of #46. It was easier to copy the important
parts and start clean than try and delete all of the generics code.

Replace the direct dependency on Sentry with the abstract `Telemetry`
interface from @transitive-bullshit. This should have no impact on
users who weren't using the Sentry integration, and requires passing
Sentry as an argument when creating a model instance.

```ts
import { ChatModel } from '@dexaai/dexter'
import * as Sentry from '@sentry/node'

const model = new ChatModel({ telemetry: Sentry })
```