Properly configure conformance tests to run source status conformance test against KafkaSource

[devguyio]

Problem
Eventing added the ability to test sources status conformance in knative/eventing#3605 . We need to do the following to run this test against Kafka Source

1. Add a new test case that will use the helper from eventing.
2. Add a KafkaSource initialization function to and properly configure the conformance tests ComponentsTestRunner

Exit Criteria
A measurable (binary) test that would indicate that the problem has been resolved.

Time Estimate (optional):
0.5 d

Extra Context
Eventing issue knative/eventing#3117

[devguyio]

/area sources
/area test-and-release
/assign

[knative-prow-robot]

@devguyio: The label(s) area/sources cannot be applied, because the repository doesn't have them

In response to this:

/area sources
/area test-and-release
/assign

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[devguyio]

/area kafka