bots: Put back pcp dependencies onto debian-testing image

pcp has been back in testing for two months
(https://tracker.debian.org/pkg/pcp).

PR #8968 will the actually make use of it.

Closes #9043

bots/images/scripts/debian.setup

@@ -69,9 +69,6 @@ case "$RELEASE" in
         ;;
 
     testing)
-        # https://tracker.debian.org/pcp not currently in testing
-        COCKPIT_DEPS="${COCKPIT_DEPS/libpcp3 /}"
-        COCKPIT_DEPS="${COCKPIT_DEPS/pcp /}"
         COCKPIT_DEPS="${COCKPIT_DEPS} libblockdev-mdraid2 udisks2-lvm2"
 
         # docker.io got removed from testing; use backports-version