test_sentry: Fix sentry DSN format
Latest sentry-sdk release now raises a BadDsn exception when DSN format does not match the expected one.
See https://jenkins.softwareheritage.org/job/DENV/job/run-all-tests/666/artifact/swh-core.log
Staging instance, all changes can be removed at any time
Latest sentry-sdk release now raises a BadDsn exception when DSN format does not match the expected one.
See https://jenkins.softwareheritage.org/job/DENV/job/run-all-tests/666/artifact/swh-core.log