Add type checks to generated methods

### What problem are you facing?

Before generation was used for claim / class / managed resource methods, we made sure that methods were implemented such that each struct satisfied its desired interface. For example:

```go
var _ resource.Claim = &RedisCluster{}
```

### How could Crossplane help solve your problem?

Though these type checks are less important now that the methods are generated, they are helpful for someone who is trying to understand how these types are used in `crossplane-runtime`. It would be useful to generate these type checks alongside the methods.

Locate the generator that emits claim, class, and managed resource methods, then review how its generated output is structured. Add generated interface type checks alongside those methods and verify that the generated types satisfy their intended crossplane-runtime interfaces.

Written by the indexing model from the issue text.