casper: Fix invalid check in 00-realm-creation.
casper: Fix invalid check in 00-realm-creation.

We shouldn't be checking for #zfilt here, since we haven't done
anything that should cause #zfilt to load.  Instead, we verify whether
messages have loaded into the DOM (the condition we actually want) by
checking whether at least one message row is in the DOM.

punchagan/zulip,hackerkid/zulip,rht/zulip,kou/zulip,shubhamdhama/zulip,andersk/zulip,kou/zulip,showell/zulip,punchagan/zulip,kou/zulip,brainwane/zulip,hackerkid/zulip,zulip/zulip,andersk/zulip,rht/zulip,timabbott/zulip,rht/zulip,showell/zulip,punchagan/zulip,eeshangarg/zulip,punchagan/zulip,timabbott/zulip,eeshangarg/zulip,showell/zulip,andersk/zulip,kou/zulip,brainwane/zulip,shubhamdhama/zulip,kou/zulip,rht/zulip,zulip/zulip,synicalsyntax/zulip,synicalsyntax/zulip,kou/zulip,showell/zulip,shubhamdhama/zulip,timabbott/zulip,synicalsyntax/zulip,zulip/zulip,hackerkid/zulip,timabbott/zulip,brainwane/zulip,punchagan/zulip,hackerkid/zulip,brainwane/zulip,rht/zulip,shubhamdhama/zulip,eeshangarg/zulip,rht/zulip,andersk/zulip,eeshangarg/zulip,hackerkid/zulip,shubhamdhama/zulip,shubhamdhama/zulip,punchagan/zulip,eeshangarg/zulip,shubhamdhama/zulip,synicalsyntax/zulip,synicalsyntax/zulip,synicalsyntax/zulip,andersk/zulip,hackerkid/zulip,punchagan/zulip,synicalsyntax/zulip,eeshangarg/zulip,rht/zulip,showell/zulip,timabbott/zulip,timabbott/zulip,eeshangarg/zulip,hackerkid/zulip,zulip/zulip,brainwane/zulip,timabbott/zulip,zulip/zulip,andersk/zulip,showell/zulip,brainwane/zulip,showell/zulip,kou/zulip,zulip/zulip,andersk/zulip,brainwane/zulip,zulip/zulip