[llvm] Fix bazel build after 185a23e.

[bartchr808]

Was failing with

ERROR: /var/lib/buildkite-agent/.cache/bazel/_bazel_buildkite-agent/c9d34ded3a9d94cc250207948aceadfc/external/llvm-project/llvm/unittests/BUILD.bazel:505:8: Compiling llvm/unittests/Frontend/PropertySetRegistryTest.cpp failed: (Exit 1): clang failed: error executing CppCompile command (from target @@llvm-project//llvm/unittests:frontend_tests) /usr/lib/llvm-18/bin/clang -U_FORTIFY_SOURCE -fstack-protector -Wall -Wthread-safety -Wself-assign -Wunused-but-set-parameter -Wno-free-nonheap-object -fcolor-diagnostics -fno-omit-frame-pointer ... (remaining 151 arguments skipped)
--
  |  
  | Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
  | external/llvm-project/llvm/unittests/Frontend/PropertySetRegistryTest.cpp:10:10: error: module llvm-project//llvm/unittests:frontend_tests does not depend on a module exporting 'llvm/Frontend/Offloading/PropertySet.h'
  | 10 \| #include "llvm/Frontend/Offloading/PropertySet.h"