counts.py: Change pull_function to take a property instead of a full stat.
counts.py: Change pull_function to take a property instead of a full stat.

Removes the circular dependency of CountStat containing a DataCollector, and
DataCollector containing a function that takes a CountStat as an argument.

andersk/zulip,rishig/zulip,tommyip/zulip,synicalsyntax/zulip,amanharitsh123/zulip,punchagan/zulip,punchagan/zulip,mahim97/zulip,jackrzhang/zulip,andersk/zulip,tommyip/zulip,showell/zulip,timabbott/zulip,jackrzhang/zulip,vabs22/zulip,verma-varsha/zulip,mahim97/zulip,rht/zulip,shubhamdhama/zulip,SmartPeople/zulip,vaidap/zulip,rht/zulip,eeshangarg/zulip,verma-varsha/zulip,rht/zulip,Galexrt/zulip,j831/zulip,synicalsyntax/zulip,christi3k/zulip,zulip/zulip,brainwane/zulip,shubhamdhama/zulip,vabs22/zulip,jackrzhang/zulip,zulip/zulip,showell/zulip,rishig/zulip,dhcrzf/zulip,vaidap/zulip,jrowan/zulip,SmartPeople/zulip,rishig/zulip,timabbott/zulip,rishig/zulip,vabs22/zulip,zulip/zulip,brainwane/zulip,christi3k/zulip,zulip/zulip,rht/zulip,showell/zulip,Galexrt/zulip,kou/zulip,tommyip/zulip,ryanbackman/zulip,dhcrzf/zulip,punchagan/zulip,mahim97/zulip,dhcrzf/zulip,hackerkid/zulip,zulip/zulip,brainwane/zulip,brockwhittaker/zulip,verma-varsha/zulip,andersk/zulip,brainwane/zulip,jrowan/zulip,ryanbackman/zulip,hackerkid/zulip,vabs22/zulip,jackrzhang/zulip,verma-varsha/zulip,punchagan/zulip,synicalsyntax/zulip,jrowan/zulip,jphilipsen05/zulip,amanharitsh123/zulip,synicalsyntax/zulip,tommyip/zulip,jphilipsen05/zulip,tommyip/zulip,zulip/zulip,j831/zulip,showell/zulip,vaidap/zulip,jphilipsen05/zulip,brainwane/zulip,dhcrzf/zulip,j831/zulip,shubhamdhama/zulip,brainwane/zulip,rishig/zulip,ryanbackman/zulip,eeshangarg/zulip,amanharitsh123/zulip,synicalsyntax/zulip,SmartPeople/zulip,dhcrzf/zulip,hackerkid/zulip,brainwane/zulip,jrowan/zulip,hackerkid/zulip,eeshangarg/zulip,kou/zulip,punchagan/zulip,timabbott/zulip,punchagan/zulip,rishig/zulip,shubhamdhama/zulip,brockwhittaker/zulip,amanharitsh123/zulip,ryanbackman/zulip,hackerkid/zulip,brockwhittaker/zulip,hackerkid/zulip,SmartPeople/zulip,showell/zulip,synicalsyntax/zulip,andersk/zulip,vaidap/zulip,jackrzhang/zulip,showell/zulip,vabs22/zulip,kou/zulip,vaidap/zulip,tommyip/zulip,rht/zulip,ryanbackman/zulip,punchagan/zulip,rht/zulip,mahim97/zulip,dhcrzf/zulip,tommyip/zulip,eeshangarg/zulip,andersk/zulip,jrowan/zulip,christi3k/zulip,jphilipsen05/zulip,kou/zulip,Galexrt/zulip,Galexrt/zulip,christi3k/zulip,Galexrt/zulip,mahim97/zulip,andersk/zulip,zulip/zulip,verma-varsha/zulip,synicalsyntax/zulip,amanharitsh123/zulip,jackrzhang/zulip,Galexrt/zulip,rishig/zulip,jphilipsen05/zulip,timabbott/zulip,vaidap/zulip,timabbott/zulip,mahim97/zulip,brockwhittaker/zulip,eeshangarg/zulip,dhcrzf/zulip,andersk/zulip,amanharitsh123/zulip,timabbott/zulip,shubhamdhama/zulip,eeshangarg/zulip,vabs22/zulip,jphilipsen05/zulip,Galexrt/zulip,shubhamdhama/zulip,kou/zulip,timabbott/zulip,ryanbackman/zulip,shubhamdhama/zulip,kou/zulip,j831/zulip,SmartPeople/zulip,SmartPeople/zulip,christi3k/zulip,showell/zulip,brockwhittaker/zulip,brockwhittaker/zulip,j831/zulip,rht/zulip,j831/zulip,christi3k/zulip,verma-varsha/zulip,jackrzhang/zulip,kou/zulip,eeshangarg/zulip,jrowan/zulip,hackerkid/zulip