pydrake: Mark explicit clang-format enforcement

Now all packages explicitly list whether they enable the clang-format
idempotency linter or not.  Only //bindings/pydrake/common currently has
it disabled (with a TODO).

bindings/BUILD.bazel

@@ -26,4 +26,7 @@ drake_pybind_library(
     package_info = get_bazel_workaround_4594_libdrake_package_info(),
 )
 
-add_lint_tests()
+add_lint_tests(
+    cpplint_data = ["//bindings/pydrake:.clang-format"],
+    enable_clang_format_lint = True,
+)

bindings/pydrake/common/BUILD.bazel

@@ -433,4 +433,8 @@ drake_py_unittest(
     ],
 )
 
-add_lint_tests()
+add_lint_tests(
+    cpplint_data = ["//bindings/pydrake:.clang-format"],
+    # TODO(jwnimmer-tri) We should enable this eventually.
+    enable_clang_format_lint = False,
+)

bindings/pydrake/util/BUILD.bazel

@@ -102,4 +102,7 @@ drake_py_test(
     deps = [":util"],
 )
 
-add_lint_tests()
+add_lint_tests(
+    cpplint_data = ["//bindings/pydrake:.clang-format"],
+    enable_clang_format_lint = True,
+)