test_signup: Fix the fetching of UserProfile in verify_signup.
test_signup: Fix the fetching of UserProfile in verify_signup.

get_user_by_delivery_email should be used, given that the email variable
is the realm email address that the account is being created with, not
the .email field which can be a dummy address based on org settings.

eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,eeshangarg/zulip,zulip/zulip,andersk/zulip,kou/zulip,kou/zulip,rht/zulip,zulip/zulip,andersk/zulip,zulip/zulip,zulip/zulip,eeshangarg/zulip,rht/zulip,andersk/zulip,andersk/zulip,andersk/zulip,andersk/zulip,andersk/zulip,kou/zulip,kou/zulip,rht/zulip,eeshangarg/zulip,eeshangarg/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,zulip/zulip,rht/zulip,kou/zulip,kou/zulip,rht/zulip,kou/zulip,rht/zulip