chore(users/Profpatsch): replace Label with pa-label

We upstreamed some of these modules to hackage, so I can get rid of it
here.

Change-Id: I70e1e864a81029cadbbd96cc019a768728431cff
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8659
Reviewed-by: Profpatsch <mail@profpatsch.de>
Tested-by: BuildkiteCI
Autosubmit: Profpatsch <mail@profpatsch.de>
Reviewed-by: sterni <sternenseemann@systemli.org>

users/Profpatsch/my-prelude/my-prelude.cabal

@@ -7,7 +7,6 @@ maintainer:         mail@profpatsch.de
 library
     exposed-modules:
       MyPrelude
-      Label
       Pretty
       Data.Error.Tree
       Aeson
@@ -21,6 +20,7 @@ library
     -- other-extensions:
     build-depends:
        base >=4.15 && <5
+     , pa-label
      , aeson
      , aeson-better-errors
      , PyF