Refine timeouts for the public CI to pass tests consistently

[ghost]

With some recent tests, we stumble once in a while on flaky tests in the public CI, that we do not see in the private one. For instance, we can see on #100 that the public CI fails (due to a timeout of 10000 ms on one test) while the private one succeeds.

We should increase these timeouts a bit for the tests to pass consistently, no matter what the resources available are in the associated infrastructure.