[Enhancement] [TEST] Remove hardcoded node uri from tests

[moritzkirstein]

Motivation / Problem

Currently the node uri to be used for integration tests is hardcoded in the test files. It should be available from the ocean config however.

Solution

Remove hardcoded uri and use the one from ocean config.

Alternatives

Additional context

Was initially hardcoded because a different uri needed to be used, rather than the one specified. We could allow overwriting via env.