Fix stream_push_notify feature to not send emails.
Fix stream_push_notify feature to not send emails.

Previously, due to a logic bug, this feature would also send email
notifications for all messages on the stream, which is definitely not
the intent.  The recent refactoring we just did makes the logic more
obvious.

synicalsyntax/zulip,jackrzhang/zulip,hackerkid/zulip,amanharitsh123/zulip,tommyip/zulip,dhcrzf/zulip,eeshangarg/zulip,Galexrt/zulip,rishig/zulip,shubhamdhama/zulip,zulip/zulip,rishig/zulip,rht/zulip,kou/zulip,rishig/zulip,zulip/zulip,andersk/zulip,Galexrt/zulip,brainwane/zulip,shubhamdhama/zulip,hackerkid/zulip,zulip/zulip,amanharitsh123/zulip,punchagan/zulip,rht/zulip,showell/zulip,punchagan/zulip,tommyip/zulip,dhcrzf/zulip,mahim97/zulip,showell/zulip,hackerkid/zulip,hackerkid/zulip,mahim97/zulip,showell/zulip,synicalsyntax/zulip,verma-varsha/zulip,kou/zulip,eeshangarg/zulip,brockwhittaker/zulip,amanharitsh123/zulip,shubhamdhama/zulip,shubhamdhama/zulip,verma-varsha/zulip,synicalsyntax/zulip,synicalsyntax/zulip,zulip/zulip,brockwhittaker/zulip,jackrzhang/zulip,timabbott/zulip,amanharitsh123/zulip,showell/zulip,verma-varsha/zulip,hackerkid/zulip,synicalsyntax/zulip,punchagan/zulip,punchagan/zulip,punchagan/zulip,brainwane/zulip,kou/zulip,verma-varsha/zulip,brainwane/zulip,eeshangarg/zulip,timabbott/zulip,kou/zulip,verma-varsha/zulip,timabbott/zulip,rht/zulip,eeshangarg/zulip,mahim97/zulip,rishig/zulip,hackerkid/zulip,jackrzhang/zulip,brockwhittaker/zulip,rishig/zulip,dhcrzf/zulip,eeshangarg/zulip,jackrzhang/zulip,synicalsyntax/zulip,tommyip/zulip,tommyip/zulip,showell/zulip,kou/zulip,shubhamdhama/zulip,Galexrt/zulip,brockwhittaker/zulip,brainwane/zulip,brainwane/zulip,mahim97/zulip,showell/zulip,punchagan/zulip,jackrzhang/zulip,brockwhittaker/zulip,eeshangarg/zulip,andersk/zulip,punchagan/zulip,timabbott/zulip,andersk/zulip,brainwane/zulip,andersk/zulip,brainwane/zulip,zulip/zulip,andersk/zulip,brockwhittaker/zulip,synicalsyntax/zulip,mahim97/zulip,verma-varsha/zulip,hackerkid/zulip,dhcrzf/zulip,kou/zulip,rishig/zulip,rht/zulip,Galexrt/zulip,timabbott/zulip,Galexrt/zulip,eeshangarg/zulip,dhcrzf/zulip,andersk/zulip,timabbott/zulip,shubhamdhama/zulip,jackrzhang/zulip,jackrzhang/zulip,tommyip/zulip,rht/zulip,zulip/zulip,tommyip/zulip,amanharitsh123/zulip,showell/zulip,shubhamdhama/zulip,dhcrzf/zulip,rishig/zulip,zulip/zulip,kou/zulip,Galexrt/zulip,tommyip/zulip,dhcrzf/zulip,rht/zulip,amanharitsh123/zulip,mahim97/zulip,andersk/zulip,timabbott/zulip,Galexrt/zulip,rht/zulip