Meltano

hi, i've noticed the mapper `meltano-map-transformer` doesn't seem to override for environments? is this expected behavior?

basically doing this
```    - name: change-table-name
      config:
        stream_maps:
          y_production-x:
            __alias__: x_meltano
          y_beta-x:
            __alias__: x_meltano
          y_local-x:
            __alias__: x_meltano```
at the root rather than nested under enviroments

Please do give <https://github.com/meltano/meltano/issues/7848> a :+1: if it sounds like the same issue :pray: