delete import of gitleaks docker image

tests/CI_docker/context/misac_helpdesk_ci.docker

-FROM zricethezav/gitleaks:latest as gitleaks
-
 FROM condaforge/miniforge3:latest as conda
 
-COPY --from=gitleaks /usr/bin/gitleaks /usr/bin/
-
 # install needed system packages (without libgl1, cv2 cannot be imported)
 RUN apt update && apt install -y libgl1