Fix redundant import warnings

[benley]

These were introduced in eddf6d6

src/TailscaleManager/Config.hs:6:1: warning: [-Wunused-imports]
    The import of ‘Data.Aeson’ is redundant
      except perhaps to import instances from ‘Data.Aeson’
    To import instances alone, use: import Data.Aeson()
  |
6 | import Data.Aeson (eitherDecodeFileStrict)
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
src/TailscaleManager/Config.hs:8:1: warning: [-Wunused-imports]
    The qualified import of ‘Data.ByteString.Lazy’ is redundant
      except perhaps to import instances from ‘Data.ByteString.Lazy’
    To import instances alone, use: import Data.ByteString.Lazy()
  |
8 | import Data.ByteString.Lazy qualified as LB
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[dhyanio]

LGTM