chore(3p/sources): Bump channels & overlays

- Adjust to ecl 23.9.9 release

- Regenerate go protos after protoc-gen-go update

- Drop dhall fork which hasn't kept up with 1.42.*

- Address new clippy warnings:

  - Variant naming of Error::ValidationError
  - Simplify .try_into().unwrap()
  - Drop unnecessary identity function
  - Test module must be last in file
  - Drop unused `pub use`

- Update agenix to 0.15.0. Current master has a installCheckPhase that
  doesn't work with C++ Nix 2.3.*:
  a23aa271be (commitcomment-137185861)

Change-Id: Ic29eef20d6fd1362ce1031364a5ca6b4edf195bd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10615
Reviewed-by: aspen <root@gws.fyi>
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>

tvix/glue/src/builtins/derivation.rs

@@ -526,5 +526,3 @@ pub(crate) mod derivation_builtins {
         Ok(Value::String(NixString::new_context_from(context, &path)))
     }
 }
-
-pub use derivation_builtins::builtins as derivation_builtins;