Fix HTTP client retry mechanism

[yaronya]

We recently experienced flakiness in the 029_provider harness test where consecutive call to get the recently created provider fails (see test_provider_data data resource that was commented out in #876)

I explicitly tried to search for the log of Received a failed or not found response, retrying request as specified here but couldn't find it in the log - meaning that it might not work

We should fix it and validate that it indeed works. We could validate it with:

1. Manually create a provider (or any other resource) @ env0
2. Manually remove it
3. Configure a data resource against it - and see whether http client retries or not (with validating that the actual log is printed)

Please note to undo the changes of #876 too.

[TomerHeber]

@yaronya

Generally retry will occur if INTEGRATION_TESTS environment variable is set to 1.
Is that the case?