invitations: Move spammer check from do_invite_users into its own function.
invitations: Move spammer check from do_invite_users into its own function.

zulip/zulip,dhcrzf/zulip,jackrzhang/zulip,shubhamdhama/zulip,synicalsyntax/zulip,kou/zulip,eeshangarg/zulip,timabbott/zulip,punchagan/zulip,punchagan/zulip,showell/zulip,jackrzhang/zulip,punchagan/zulip,andersk/zulip,dhcrzf/zulip,punchagan/zulip,andersk/zulip,rht/zulip,tommyip/zulip,synicalsyntax/zulip,showell/zulip,zulip/zulip,timabbott/zulip,shubhamdhama/zulip,hackerkid/zulip,mahim97/zulip,dhcrzf/zulip,showell/zulip,tommyip/zulip,synicalsyntax/zulip,dhcrzf/zulip,brainwane/zulip,rishig/zulip,kou/zulip,showell/zulip,synicalsyntax/zulip,andersk/zulip,rht/zulip,mahim97/zulip,andersk/zulip,rht/zulip,rht/zulip,timabbott/zulip,dhcrzf/zulip,tommyip/zulip,hackerkid/zulip,shubhamdhama/zulip,mahim97/zulip,jackrzhang/zulip,synicalsyntax/zulip,kou/zulip,brainwane/zulip,eeshangarg/zulip,hackerkid/zulip,synicalsyntax/zulip,rht/zulip,eeshangarg/zulip,brainwane/zulip,eeshangarg/zulip,rht/zulip,eeshangarg/zulip,jackrzhang/zulip,punchagan/zulip,dhcrzf/zulip,brainwane/zulip,shubhamdhama/zulip,brainwane/zulip,brainwane/zulip,tommyip/zulip,shubhamdhama/zulip,rishig/zulip,rishig/zulip,brainwane/zulip,synicalsyntax/zulip,tommyip/zulip,tommyip/zulip,zulip/zulip,andersk/zulip,jackrzhang/zulip,mahim97/zulip,punchagan/zulip,jackrzhang/zulip,punchagan/zulip,hackerkid/zulip,rishig/zulip,rishig/zulip,rishig/zulip,andersk/zulip,showell/zulip,rht/zulip,jackrzhang/zulip,rishig/zulip,kou/zulip,kou/zulip,shubhamdhama/zulip,zulip/zulip,eeshangarg/zulip,timabbott/zulip,zulip/zulip,zulip/zulip,hackerkid/zulip,mahim97/zulip,andersk/zulip,zulip/zulip,timabbott/zulip,showell/zulip,kou/zulip,eeshangarg/zulip,hackerkid/zulip,mahim97/zulip,timabbott/zulip,kou/zulip,hackerkid/zulip,shubhamdhama/zulip,timabbott/zulip,dhcrzf/zulip,showell/zulip,tommyip/zulip