test: workaround cyclic dependency bzlmod bug by disabling lockfiles (#1705)

Bazel 7.0.1 has a bug where lockfiles can cause a bogus error about
cyclic dependencies. Removing the lockfile or disabling the lockfiles
prevents it from triggering. We aren't
using lockfiles anyways.

This should make CI happy, which uses 7.0.1 in some configurations.
Local development
isn't impacted because .bazelversion specifies 7.0.0

See https://github.com/bazelbuild/bazel/issues/20942

.bazelrc

diff --git a/.bazelrc b/.bazelrc
index 9ecb892..0037a96 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -30,3 +30,6 @@
 build:rtd --stamp
 # Some bzl files contain repos only available under bzlmod
 build:rtd --enable_bzlmod
+
+# Disabled due to https://github.com/bazelbuild/bazel/issues/20942
+build --lockfile_mode=off