test: prevent error in CTS personalization test on 429 HTTP code

[aseure]

The personalization API is now limiting the number of
set_personalization_strategy() successful calls to 15 per day. Because of
that, our integration tests against the real API is not returning the following
error very often on our testing application:

{
    "status": 429,
    "message": "Number of strategy saves exceeded for the day"
}

Because of that, if the CTS is implemented in the client, we need to perform
the set_personalization_strategy() call in our integration test like before
but to prevent the test from failing if the 429 error is returned (considered
it as a "success" and moving on with the get_personalization_strategy() call).

[chloelbn]

The CTS is not implemented in the PHP client, therefore nothing needs to be done here