Add override constraints tests.

**Summary**

Currently override constraints have not been yet implemented. Once these 2 will be `Done`, test cases that cover the functionality should be added to the test suite.

- https://github.com/Kuadrant/kuadrant-operator/issues/473
- https://github.com/Kuadrant/kuadrant-operator/issues/474

**Documentation**

Examples could be found here: https://docs.kuadrant.io/1.0.x/architecture/rfcs/0009-defaults-and-overrides/#examples-e-override-policy-rules-setting-constraints-to-other-at-lower-level

First review issues 473 and 474 to confirm the override-constraint functionality is implemented, then read the linked defaults-and-overrides examples. Locate the existing tests in the Kuadrant testsuite and add coverage for the documented override cases; done means the relevant scenarios run successfully in the suite.

Written by the indexing model from the issue text.