Fix broken type in toolchain.bzl

Summary:
See title. In D60309384, RE was enabled for diff-time tests. However that ended up adding a dependency on the toolchain.bzl file, which had types updated in D54263379.

This one line was causing an error in Autodeps due to the fact that Python cannot handle the `|` operator for some union types.

This is a temporary fix while we figure out a more permanent solution.

Got multiple reports on this in the workplace group:

- https://fb.workplace.com/groups/autodeps.users/posts/2698732626961886/?comment_id=2698765646958584

- https://fb.workplace.com/groups/autodeps.users/permalink/2698809960287486/

Reviewed By: stanleyz510

Differential Revision: D60417799

fbshipit-source-id: e50c62b227d288fccd6b0e3d684476357c5af962

prelude/go/toolchain.bzl

@@ -5,8 +5,6 @@
 # License, Version 2.0 found in the LICENSE-APACHE file in the root directory
 # of this source tree.
 
-load("@prelude//cxx:cxx_toolchain_types.bzl", "CxxToolchainInfo")
-
 GoToolchainInfo = provider(
     # @unsorted-dict-items
     fields = {
@@ -21,7 +19,8 @@ GoToolchainInfo = provider(
         "compiler_flags": provider_field(typing.Any, default = None),
         "concat_files": provider_field(RunInfo),
         "cover": provider_field(RunInfo),
-        "cxx_toolchain_for_linking": provider_field(CxxToolchainInfo | None, default = None),
+        # Type should be (CxxToolchainInfo | None), but setting to typing.Any for now to mitigate another issue.
+        "cxx_toolchain_for_linking": provider_field(typing.Any, default = None),  # CxxToolchainInfo | None
         "env_go_arch": provider_field(str),
         "env_go_os": provider_field(str),
         "env_go_arm": provider_field(str | None, default = None),