tests: Rename 'message.json' to 'messages-000001.json' in export tests.
tests: Rename 'message.json' to 'messages-000001.json' in export tests.

The export script produces messages in the format 'messages-%06d.json'.
Hence we rename it to 'messages-000001.json'.

dhcrzf/zulip,zulip/zulip,showell/zulip,showell/zulip,punchagan/zulip,kou/zulip,eeshangarg/zulip,dhcrzf/zulip,punchagan/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,rishig/zulip,timabbott/zulip,tommyip/zulip,brainwane/zulip,punchagan/zulip,rht/zulip,showell/zulip,timabbott/zulip,hackerkid/zulip,timabbott/zulip,rht/zulip,rishig/zulip,dhcrzf/zulip,synicalsyntax/zulip,zulip/zulip,synicalsyntax/zulip,shubhamdhama/zulip,showell/zulip,shubhamdhama/zulip,kou/zulip,timabbott/zulip,rishig/zulip,brainwane/zulip,jackrzhang/zulip,tommyip/zulip,shubhamdhama/zulip,dhcrzf/zulip,dhcrzf/zulip,hackerkid/zulip,timabbott/zulip,andersk/zulip,eeshangarg/zulip,eeshangarg/zulip,timabbott/zulip,rht/zulip,kou/zulip,shubhamdhama/zulip,showell/zulip,jackrzhang/zulip,hackerkid/zulip,zulip/zulip,showell/zulip,hackerkid/zulip,tommyip/zulip,andersk/zulip,rht/zulip,dhcrzf/zulip,punchagan/zulip,kou/zulip,zulip/zulip,rishig/zulip,tommyip/zulip,kou/zulip,punchagan/zulip,tommyip/zulip,jackrzhang/zulip,brainwane/zulip,rht/zulip,brainwane/zulip,shubhamdhama/zulip,rishig/zulip,synicalsyntax/zulip,andersk/zulip,showell/zulip,eeshangarg/zulip,hackerkid/zulip,rht/zulip,dhcrzf/zulip,synicalsyntax/zulip,hackerkid/zulip,zulip/zulip,rishig/zulip,rishig/zulip,eeshangarg/zulip,jackrzhang/zulip,punchagan/zulip,eeshangarg/zulip,shubhamdhama/zulip,andersk/zulip,brainwane/zulip,andersk/zulip,zulip/zulip,brainwane/zulip,jackrzhang/zulip,punchagan/zulip,jackrzhang/zulip,synicalsyntax/zulip,rht/zulip,shubhamdhama/zulip,brainwane/zulip,jackrzhang/zulip,hackerkid/zulip,tommyip/zulip,synicalsyntax/zulip,andersk/zulip,synicalsyntax/zulip,kou/zulip,tommyip/zulip,timabbott/zulip,zulip/zulip