Draft: Fix agentk FIPS build

• Fix agentk FIPS build

Closes #604 (closed)

Successful build:

docker buildx build -f build/agentk.ubi8-fips.Dockerfile . --build-arg 'BUILDER_IMAGE=gitlab/gitlab-agent-ci-image:latest-fips@sha256:0add4c1043010031b80e8457f1c862b90020081327192e85859fc36518cbec6c' --no-cache
[+] Building 41.2s (13/13) FINISHED
 => [internal] load build definition from agentk.ubi8-fips.Dockerfile                                                                                                                                                                                                                    0.0s
 => => transferring dockerfile: 958B                                                                                                                                                                                                                                                     0.0s
 => [internal] load .dockerignore                                                                                                                                                                                                                                                        0.0s
 => => transferring context: 259B                                                                                                                                                                                                                                                        0.0s
 => [internal] load metadata for registry.access.redhat.com/ubi8/ubi-micro:8.8                                                                                                                                                                                                           1.0s
 => [internal] load metadata for docker.io/gitlab/gitlab-agent-ci-image:latest-fips@sha256:0add4c1043010031b80e8457f1c862b90020081327192e85859fc36518cbec6c                                                                                                                              0.0s
 => [builder 1/5] FROM docker.io/gitlab/gitlab-agent-ci-image:latest-fips@sha256:0add4c1043010031b80e8457f1c862b90020081327192e85859fc36518cbec6c                                                                                                                                        0.0s
 => [internal] load build context                                                                                                                                                                                                                                                        0.3s
 => => transferring context: 748.82kB                                                                                                                                                                                                                                                    0.3s
 => CACHED [stage-1 1/2] FROM registry.access.redhat.com/ubi8/ubi-micro:8.8@sha256:2c15d47056a573b30e608c4df43d20f79b064a8c10cb8b0c020912edf00c2399                                                                                                                                      0.0s
 => CACHED [builder 2/5] WORKDIR /src                                                                                                                                                                                                                                                    0.0s
 => [builder 3/5] COPY . /src                                                                                                                                                                                                                                                            0.4s
 => [builder 4/5] RUN git config --global --add safe.directory /src                                                                                                                                                                                                                      0.2s
 => [builder 5/5] RUN TARGET_DIRECTORY=. FIPS_MODE=1 make agentk                                                                                                                                                                                                                        38.6s
 => [stage-1 2/2] COPY --from=builder /src/agentk /usr/bin/agentk                                                                                                                                                                                                                        0.2s
 => exporting to image                                                                                                                                                                                                                                                                   0.2s
 => => exporting layers                                                                                                                                                                                                                                                                  0.2s
 => => writing image sha256:f7456aa5fa6048e943697d956627b392cba794bd96365b0c19c82ce5d058b64b