test_cli.rb - fix bind port (9292 port in use errors) [changelog skip]

[MSP-Greg]

Description

Noticed intermittent test failures re 'port already in use' on port 9292, which is the default. Change two tests using it to use port 0, they aren't actually using as a client, but they are binding to it...

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[dentarg]

Change two tests using it to use port 0

I remembered some previous discussion about "port 0" vs UniquePort.call, it happened in #2270, and it sounds like "port 0" is the future for Puma so 👍