Add retries to move cv call in test.

[jctanner]

The mock insights proxy occasionally has trouble reading/writing to the nginx service and results in a broken pipe error. This PR attempts to retry 2 problematic calls that make tests regularly fail in github actions.

The failures can be reproduced locally by starting up the oci insights profile and running test_move_cv in a loop. It seems to happen less often on my local system than it does on github, but I'm chalking that up to resource constraints in the action workers.

[jctanner]

ci-insights-proxy-1         | Proxying request to: /api/automation-hub/pulp/api/v3/repositories/ansible/ansible/
ci-insights-proxy-1         | ------------- ERROR ----------------
ci-insights-proxy-1         | Post "http://pulp:55001/api/automation-hub/pulp/api/v3/repositories/ansible/ansible/": readfrom tcp 172.29.0.2:58862->172.29.0.3:55001: write tcp 172.29.0.2:58862->172.29.0.3:55001: write: broken pipe
ci-insights-proxy-1         | ------------ ERROR END -------------
ci-insights-proxy-1         | 
ci-insights-proxy-1         |