Revert "go_repository: fix missing default GOPROXY (#1602)" (#1609)

This reverts commit adce430.

We found an alternative fix to this to this issue in
bazel-contrib/rules_go#3666.

internal/go_repository.bzl

@@ -115,9 +115,6 @@ Authorization: Bearer RANDOM-TOKEN
 # We can't disable timeouts on Bazel, but we can set them to large values.
 _GO_REPOSITORY_TIMEOUT = 86400
 
-# Default value from `go env GOPROXY`
-_GOPROXY_DEFAULT = "https://proxy.golang.org,direct"
-
 def _go_repository_impl(ctx):
     # TODO(#549): vcs repositories are not cached and still need to be fetched.
     # Download the repository or module.
@@ -240,10 +237,6 @@ def _go_repository_impl(ctx):
 
     env.update({k: ctx.os.environ[k] for k in env_keys if k in ctx.os.environ})
 
-    # Since Go 1.21.0, GOPROXY must be set to a non-empty value.
-    if "GOPROXY" not in env:
-        env["GOPROXY"] = _GOPROXY_DEFAULT
-
     if fetch_repo_args:
         # Disable sumdb in fetch_repo. In module mode, the sum is a mandatory
         # attribute of go_repository, so we don't need to look it up.