e2e: cozyreport lists a shared zpool twice and ships an empty zfs-pools.txt that does not say why #4809

The LINSTOR ZFS collection that #4657 adds to hack/cozyreport.sh has two small legibility problems. Neither loses data, both make the report harder to read.

A zpool behind two LINSTOR storage pools is reported twice in the per-node listing. The satellite script cuts each dataset name down to its pool with ${d%%/*}, so pools on tank/a and tank/b pass tank tank to zpool get. zfs list drops duplicate arguments, zpool get does not. Deduplicating the pool names before the call fixes it, either with sort -u or by skipping a name already seen in the loop.

linstor/zfs-pools.txt can ship empty. When LINSTOR has no ZFS storage pool, the jq filter prints nothing and the read exits 0. Each node's note then says "that file says whether LINSTOR answered", and a 0-byte file says nothing by itself. The rule exists (0 bytes and no COLLECTION-FAILED.txt entry means LINSTOR answered with no ZFS pool), it just isn't written where the reader looks. A # [cozyreport] comment line written into the file when no pool matched would fix it. The per-node awk lookup needs a tab-separated node name in the first field, so a comment line is never taken for a pool.