re-enable bzlmod for asan build once grpc > v1.68.0 available in BCR

[scotthart]

asan bzlmod builds with v1.68.0 were failing with ODR violations that aren't present when building without bzlmod

https://storage.googleapis.com/cloud-cpp-community-publiclogs/logs/google-cloud-cpp/14869/f23d58938093130642787d8d44a94703b103fc5e/fedora-latest-bazel-asan-__default__/log-1d8fce99-1dfa-4969-8cf7-4ff3bf4f9eb1.txt

FAIL: //google/cloud:internal_routing_matcher_test (see /h/.cache/bazel/_bazel_root/eab0d61a99b6696edb3d2aff87b585e8/execroot/_main/bazel-out/k8-fastbuild/testlogs/google/cloud/internal_routing_matcher_test/test.log)
==================== Test output for //google/cloud:internal_routing_matcher_test:
=================================================================
==12==ERROR: AddressSanitizer: odr-violation (0x7f03b4e8a4e0):
  [1] size=40 'validate_validate_proto_upb_file_layout' bazel-out/k8-fastbuild/bin/external/grpc~~grpc_repo_deps_ext~com_envoyproxy_protoc_gen_validate/validate/validate.upb_minitable.c:887:25 in /h/.cache/bazel/_bazel_root/eab0d61a99b6696edb3d2aff87b585e8/execroot/_main/bazel-out/k8-fastbuild/bin/google/cloud/../../_solib_k8/libexternal_Sgrpc~~grpc_Urepo_Udeps_Uext~com_Uenvoyproxy_Uprotoc_Ugen_Uvalidate_Svalidate_Slibvalidate_Uproto.upb_Uminitable.so
  [2] size=40 'validate_validate_proto_upb_file_layout' bazel-out/k8-fastbuild/bin/external/protoc-gen-validate~/validate/validate.upb_minitable.c:887:25 in /h/.cache/bazel/_bazel_root/eab0d61a99b6696edb3d2aff87b585e8/execroot/_main/bazel-out/k8-fastbuild/bin/google/cloud/../../_solib_k8/libexternal_Sprotoc-gen-validate~_Svalidate_Slibvalidate_Uproto.upb_Uminitable.so
These globals were registered at these points:
  [1]:
    #0 0x7f03b730b5d7 in __asan_register_globals.part.0 (/lib64/libasan.so.8+0x525d7) (BuildId: a4ad7eb954b390cf00f07fa10952988a41d9fc7a)
    #1 0x7f03b4e87c0e in _sub_I_00099_1 (/h/.cache/bazel/_bazel_root/eab0d61a99b6696edb3d2aff87b585e8/execroot/_main/bazel-out/k8-fastbuild/bin/google/cloud/../../_solib_k8/libexternal_Sgrpc~~grpc_Urepo_Udeps_Uext~com_Uenvoyproxy_Uprotoc_Ugen_Uvalidate_Svalidate_Slibvalidate_Uproto.upb_Uminitable.so+0x5c0e) (BuildId: 22a5ac117e51749db60c8b76425dbcb4c7910605)
    #2 0x7f03b798f436 in call_init /usr/src/debug/glibc-2.39-22.fc40.x86_64/elf/dl-init.c:74
    #3 0x7f03b798f436 in call_init /usr/src/debug/glibc-2.39-22.fc40.x86_64/elf/dl-init.c:26
    #4 0x7f03b798f52c in _dl_init /usr/src/debug/glibc-2.39-22.fc40.x86_64/elf/dl-init.c:121
    #5 0x7f03b79a709f  (/lib64/ld-linux-x86-64.so.2+0x1d09f) (BuildId: 91dcd0244204201b616bbf59427771b3751736ce)

  [2]:
    #0 0x7f03b730b5d7 in __asan_register_globals.part.0 (/lib64/libasan.so.8+0x525d7) (BuildId: a4ad7eb954b390cf00f07fa10952988a41d9fc7a)
    #1 0x7f03b3b8abee in _sub_I_00099_1 (/h/.cache/bazel/_bazel_root/eab0d61a99b6696edb3d2aff87b585e8/execroot/_main/bazel-out/k8-fastbuild/bin/google/cloud/../../_solib_k8/libexternal_Sprotoc-gen-validate~_Svalidate_Slibvalidate_Uproto.upb_Uminitable.so+0x5bee) (BuildId: 81d0ab753ced805c966fd9998ee632de8b2efbc2)
    #2 0x7f03b798f436 in call_init /usr/src/debug/glibc-2.39-22.fc40.x86_64/elf/dl-init.c:74
    #3 0x7f03b798f436 in call_init /usr/src/debug/glibc-2.39-22.fc40.x86_64/elf/dl-init.c:26
    #4 0x7f03b798f52c in _dl_init /usr/src/debug/glibc-2.39-22.fc40.x86_64/elf/dl-init.c:121
    #5 0x7f03b79a709f  (/lib64/ld-linux-x86-64.so.2+0x1d09f) (BuildId: 91dcd0244204201b616bbf59427771b3751736ce)

==12==HINT: if you don't care about these errors you may set ASAN_OPTIONS=detect_odr_violation=0
SUMMARY: AddressSanitizer: odr-violation: global 'validate_validate_proto_upb_file_layout' at bazel-out/k8-fastbuild/bin/external/grpc~~grpc_repo_deps_ext~com_envoyproxy_protoc_gen_validate/validate/validate.upb_minitable.c:887:25 in /h/.cache/bazel/_bazel_root/eab0d61a99b6696edb3d2aff87b585e8/execroot/_main/bazel-out/k8-fastbuild/bin/google/cloud/../../_solib_k8/libexternal_Sgrpc~~grpc_Urepo_Udeps_Uext~com_Uenvoyproxy_Uprotoc_Ugen_Uvalidate_Svalidate_Slibvalidate_Uproto.upb_Uminitable.so
==12==ABORTING
================================================================================