openapi: Rectify wrong examples and schemas.
openapi: Rectify wrong examples and schemas.

Some examples mentioned in zulip.yaml did not match their schema.
Change either the schema or the example so that all examples are
valid with respect to their schemas.

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