Remove gitleaks scanning

Ref:
https://github.com/containers/podman/pull/21570#issuecomment-1935709148

This tool is really intended/best used from git pre-commit on developers
local machines, to prevent addition of secret leaks.  When used as a
check against PRs, it tends to turn up more false-positives than helpful
warnings.  There's no good way to fix this, and maintaining the scanner
is an additional burden.  Rather than continue struggling to improve/fix
the situation, let's just remove the tool entirely.

Signed-off-by: Chris Evich <cevich@redhat.com>

contrib/cirrus/prebuild.sh

@@ -71,38 +71,6 @@ if [[ "${DISTRO_NV}" == "$PRIOR_FEDORA_NAME" ]]; then
       export PREBUILD=1
       showrun bash ${CIRRUS_WORKING_DIR}/.github/actions/check_cirrus_cron/test.sh
     fi
-
-    # Note: This may detect leaks, but should not be considered authoritative
-    # since any PR could modify the contents or arguments.  This check is
-    # simply here to...
-    msg "Checking GitLeaks functions with current CLI args, configuration, and baseline JSON"
-
-    # TODO: Workaround for GHA Environment, duplicate here for consistency.
-    # Replace with `--userns=keep-id:uid=1000,gid=1000` w/ newer podman in GHA environment.
-    declare -a workaround_args
-    workaround_args=(\
-      --user 1000:1000
-      --uidmap 0:1:1000
-      --uidmap 1000:0:1
-      --uidmap 1001:1001:64536
-      --gidmap 0:1:1000
-      --gidmap 1000:0:1
-      --gidmap 1001:1001:64536
-    )
-
-    brdepth=$(get_env_key 'brdepth')
-    glfqin=$(get_env_key 'glfqin')
-    glargs=$(get_env_key 'glargs')
-    showrun podman run --rm \
-        --security-opt=label=disable \
-        "${workaround_args[@]}" \
-        -v $CIRRUS_WORKING_DIR:/subject:ro \
-        -v $CIRRUS_WORKING_DIR:/default:ro \
-        --tmpfs /report:rw,size=256k,mode=1777 \
-        $glfqin \
-        detect \
-        --log-opts=-$brdepth \
-        $glargs
 fi
 
 msg "Checking 3rd party network service connectivity"