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/castore-go/castore.pb.go

@@ -3,7 +3,7 @@
 
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.31.0
+// 	protoc-gen-go v1.32.0
 // 	protoc        (unknown)
 // source: tvix/castore/protos/castore.proto
 

tvix/castore-go/rpc_blobstore.pb.go

@@ -3,7 +3,7 @@
 
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.31.0
+// 	protoc-gen-go v1.32.0
 // 	protoc        (unknown)
 // source: tvix/castore/protos/rpc_blobstore.proto
 

tvix/castore-go/rpc_directory.pb.go

@@ -3,7 +3,7 @@
 
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.31.0
+// 	protoc-gen-go v1.32.0
 // 	protoc        (unknown)
 // source: tvix/castore/protos/rpc_directory.proto