Closes https://github.com/zed-industries/zed/issues/32984

Note that while https://github.com/zed-industries/zed/pull/33666 did the
reading of the `envFile` just fine, the read values were never passed
along. This was mentioned by [this
comment](https://github.com/zed-industries/zed/pull/33666#issuecomment-3060785970)
and also confirmed by myself.

With the changes here, I successfully debugged a project of mine and all
the environment variables from my `.env` were present.

Release Notes:

- Fix Go debugger ignoring env vars from the envFile setting.