test_home: Fix wrong bot references in test_people.
test_home: Fix wrong bot references in test_people.

These are all referring to email_gateway_bot, when they're supposed to
refer to the notification and welcome bots, respectively. The values are
the same though, so the tests were passing anyway.

hackerkid/zulip,eeshangarg/zulip,punchagan/zulip,hackerkid/zulip,kou/zulip,kou/zulip,andersk/zulip,kou/zulip,punchagan/zulip,eeshangarg/zulip,kou/zulip,kou/zulip,zulip/zulip,rht/zulip,rht/zulip,kou/zulip,andersk/zulip,zulip/zulip,andersk/zulip,eeshangarg/zulip,rht/zulip,zulip/zulip,zulip/zulip,punchagan/zulip,andersk/zulip,rht/zulip,eeshangarg/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,eeshangarg/zulip,punchagan/zulip,hackerkid/zulip,hackerkid/zulip,kou/zulip,punchagan/zulip,andersk/zulip,zulip/zulip,punchagan/zulip,zulip/zulip,andersk/zulip,rht/zulip,punchagan/zulip,hackerkid/zulip,andersk/zulip,eeshangarg/zulip,rht/zulip,hackerkid/zulip,hackerkid/zulip