test: refactor asserts

[alexandear]

Replace require.Nil/require.NotNil with more idiomatic require.NoError/require.Error. Reverse actual and expected values in a few test asserts.

Related Issue or Design Document

Checklist

• [x] I have read the contributing guidelines and signed the CLA.
• [x] I have referenced an issue containing the design document if my change introduces a new feature.
• [x] I have read the security policy.
• [x] I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security vulnerability, I confirm that I got approval (please contact security@ory.sh) from the maintainers to push the changes.
• [x] I have added tests that prove my fix is effective or that my feature works.
• [x] I have added the necessary documentation within the code base (if appropriate).

Further comments

This is found with the help of testifylint.

Running log

``` dockertest_test.go:45:2: error-nil: use require.NoError (testifylint) dockertest_test.go:57:2: error-nil: use require.NoError (testifylint) dockertest_test.go:58:2: error-nil: use require.NoError (testifylint) dockertest_test.go:70:2: error-nil: use require.NoError (testifylint) dockertest_test.go:86:2: error-nil: use require.NoError (testifylint) dockertest_test.go:87:2: error-nil: use require.NoError (testifylint) dockertest_test.go:97:2: error-nil: use require.NoError (testifylint) dockertest_test.go:108:2: error-nil: use require.NoError (testifylint) dockertest_test.go:110:2: error-nil: use require.NoError (testifylint) dockertest_test.go:120:2: error-nil: use require.NoError (testifylint) dockertest_test.go:123:2: error-nil: use require.NoError (testifylint) dockertest_test.go:138:2: error-nil: use require.NoError (testifylint) dockertest_test.go:141:2: error-nil: use require.NoError (testifylint) dockertest_test.go:154:2: error-nil: use require.NoError (testifylint) dockertest_test.go:158:2: error-nil: use require.NoError (testifylint) dockertest_test.go:161:2: error-nil: use require.NoError (testifylint) dockertest_test.go:173:2: error-nil: use require.NoError (testifylint) dockertest_test.go:177:2: error-nil: use require.NoError (testifylint) dockertest_test.go:180:2: error-nil: use require.NoError (testifylint) dockertest_test.go:193:2: error-nil: use require.NoError (testifylint) dockertest_test.go:196:2: error-nil: use require.NoError (testifylint) dockertest_test.go:210:2: error-nil: use require.NoError (testifylint) dockertest_test.go:213:2: error-nil: use require.NoError (testifylint) dockertest_test.go:243:2: error-nil: use require.NoError (testifylint) dockertest_test.go:250:2: error-nil: use require.NoError (testifylint) dockertest_test.go:252:2: expected-actual: need to reverse actual and expected values (testifylint) dockertest_test.go:253:2: error-nil: use require.NoError (testifylint) dockertest_test.go:258:2: error-nil: use require.NoError (testifylint) dockertest_test.go:273:3: error-nil: use require.NoError (testifylint) dockertest_test.go:276:3: error-nil: use require.Error (testifylint) dockertest_test.go:279:2: error-nil: use require.NoError (testifylint) dockertest_test.go:281:2: error-nil: use require.NoError (testifylint) dockertest_test.go:294:2: error-nil: use require.NoError (testifylint) dockertest_test.go:297:2: error-nil: use require.NoError (testifylint) dockertest_test.go:308:2: error-nil: use require.NoError (testifylint) dockertest_test.go:313:2: expected-actual: need to reverse actual and expected values (testifylint) dockertest_test.go:315:2: error-nil: use require.NoError (testifylint) dockertest_test.go:326:2: error-nil: use require.NoError (testifylint) dockertest_test.go:329:2: error-nil: use require.NoError (testifylint) dockertest_test.go:337:2: error-nil: use require.NoError (testifylint) dockertest_test.go:338:2: error-nil: use require.NoError (testifylint) dockertest_test.go:343:2: error-nil: use require.NoError (testifylint) dockertest_test.go:357:2: error-nil: use require.NoError (testifylint) dockertest_test.go:364:2: error-nil: use require.NoError (testifylint) dockertest_test.go:372:2: error-nil: use require.NoError (testifylint) dockertest_test.go:381:2: error-nil: use require.NoError (testifylint) dockertest_test.go:390:2: error-nil: use require.NoError (testifylint) dockertest_test.go:407:2: error-nil: use require.NoError (testifylint) dockertest_test.go:412:2: error-nil: use require.NoError (testifylint) dockertest_test.go:416:2: error-nil: use require.NoError (testifylint) dockertest_test.go:420:2: error-nil: use require.NoError (testifylint) dockertest_test.go:423:2: error-nil: use require.NoError (testifylint) dockertest_test.go:427:2: error-nil: use require.NoError (testifylint) dockertest_test.go:443:2: error-nil: use require.NoError (testifylint) dockertest_test.go:450:2: error-nil: use require.NoError (testifylint) dockertest_test.go:483:2: error-nil: use require.NoError (testifylint) dockertest_test.go:485:2: error-nil: use require.NoError (testifylint) dockertest_test.go:488:2: error-nil: use require.NoError (testifylint) ```

[alnr]

This is a good improvements. Would you mind rebasing?