Fix Bazel buildtools dependency (#4980)

* Fix Bazel module dependencies

* Import bazelbuild manually instead of through Gazelle

MODULE.bazel

@@ -60,3 +60,10 @@ use_repo(
     "org_golang_x_oauth2",
     "org_golang_x_text",
 )
+
+non_module_deps = use_extension(":non_module_deps.bzl", "non_module_deps")
+use_repo(
+    non_module_deps,
+    "com_github_bazelbuild_buildtools",
+    "org_golang_x_tools",
+)

non_module_deps.bzl

@@ -0,0 +1,25 @@
+"""Module extension for non-module dependencies."""
+
+load("@bazel_gazelle//:deps.bzl", "go_repository")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+def _non_module_deps_impl(
+        # buildifier: disable=unused-variable
+        mctx):
+    # TODO(bazelbuild/buildtools#1204): Remove when available as module.
+    go_repository(
+        name = "org_golang_x_tools",
+        importpath = "golang.org/x/tools",
+        sum = "h1:vU5i/LfpvrRCpgM/VPfJLg5KjxD3E+hfT1SH+d9zLwg=",
+        version = "v0.21.1-0.20240508182429-e35e4ccd0d2d",
+    )
+    http_archive(
+        name = "com_github_bazelbuild_buildtools",
+        sha256 = "42968f9134ba2c75c03bb271bd7bb062afb7da449f9b913c96e5be4ce890030a",
+        strip_prefix = "buildtools-6.3.3",
+        urls = ["https://github.com/bazelbuild/buildtools/archive/v6.3.3.tar.gz"],
+    )
+
+non_module_deps = module_extension(
+    implementation = _non_module_deps_impl,
+)