Add Rest API tests for bucket update endpoint (update by RP and RP + name)

Currently there is a test suite for testing bucket update endpoint to test update of the name only, since bucket creation is not handling RP correctly (just numbers and not real durations). Once the RP issue is fixed two test suites will have to be added to already existing `test_gateway_update_buckets.py` test suite

Start with test_gateway_update_buckets.py and review the existing bucket name-only update tests. First confirm that bucket creation handles RP as real durations, then add suites covering updates by RP and by RP plus name. Done means the new tests pass with the corrected RP behavior.

Written by the indexing model from the issue text.