refactor!: update MakeCluster functions to return error

- Update makeCluster to return (*cluster, error)
- Modify MakeCluster, MakeClusterNoBootstrap, and MakeClusterCustom to return error
- Update all test cases to handle potential errors from cluster creation
- Replace t.Fatalf() calls with t.Logf() and error returns in makeCluster

BREAKING CHANGE: MakeCluster, MakeClusterNoBootstrap, and MakeClusterCustom
now return an additional error value, which needs to be handled in existing tests.

Author: peterxcli