Skaffold configuration dependencies not working icw kpt deployer

### Expected behavior
When creating dependent Skaffold configurations using the `requires` key, and at least one of these configurations uses a kpt deployer, this is accepted as the individual configurations will be deployed separately.

### Actual behavior
The configurations can not be deployed as instead an error is produced:

`creating runner: creating deployer: kpt deployer mixed in with other deployers not supported yet. Please use only kpt deployer`

### Information
- Skaffold version: v2.0.3
- Operating system: MacOS 12.5
- Installed via: Homebrew

### Steps to reproduce the behavior
- Create two Skaffold configurations, at least one of which using a kpt deployer
- Have one depend on the other using a `requires` entry (both `path` and `configs` will reproduce the issue)
- Attempt to deploy the configuration which contains the `requires` entry.

The error is produced on the following line: https://github.com/GoogleContainerTools/skaffold/blob/main/pkg/skaffold/runner/deployer.go#L178
It seems the issue is that the deployers of multiple configurations are being aggregated in the deployers slice.

The issue also occurs when all the configurations use a kpt deployer.