bug: `environment_variables` and `tags` are not being set properly after the first apply

[ianaya89]

The properties environment_variables and tags are not being set properly after the first apply:

2022-03-16T17:12:24.127-0300 [WARN]  Provider "dev/checkly/checkly" produced an unexpected new value for checkly_check.browser-check during refresh.
      - .environment_variables: was null, but now cty.MapValEmpty(cty.String)
      - .tags: was null, but now cty.SetValEmpty(cty.String)