[zk] `mntr` command's `zk_packets*` as rate
[zk] `mntr` command's `zk_packets*` as rate

Report `mntr` command's `zk_packets*` information as rate, not gauge.

jyogi/purvar-agent,c960657/dd-agent,indeedops/dd-agent,Wattpad/dd-agent,pmav99/praktoras,jyogi/purvar-agent,tebriel/dd-agent,c960657/dd-agent,jyogi/purvar-agent,manolama/dd-agent,gphat/dd-agent,cberry777/dd-agent,gphat/dd-agent,cberry777/dd-agent,brettlangdon/dd-agent,pmav99/praktoras,pmav99/praktoras,Wattpad/dd-agent,cberry777/dd-agent,brettlangdon/dd-agent,gphat/dd-agent,tebriel/dd-agent,c960657/dd-agent,Wattpad/dd-agent,cberry777/dd-agent,brettlangdon/dd-agent,Wattpad/dd-agent,jyogi/purvar-agent,lookout/dd-agent,jyogi/purvar-agent,pmav99/praktoras,cberry777/dd-agent,indeedops/dd-agent,takus/dd-agent,brettlangdon/dd-agent,manolama/dd-agent,manolama/dd-agent,tebriel/dd-agent,takus/dd-agent,lookout/dd-agent,lookout/dd-agent,indeedops/dd-agent,takus/dd-agent,pmav99/praktoras,manolama/dd-agent,tebriel/dd-agent,gphat/dd-agent,brettlangdon/dd-agent,c960657/dd-agent,lookout/dd-agent,indeedops/dd-agent,tebriel/dd-agent,c960657/dd-agent,indeedops/dd-agent,gphat/dd-agent,Wattpad/dd-agent,takus/dd-agent,takus/dd-agent,lookout/dd-agent,manolama/dd-agent