[BUG] Topic does not have schema to check when the function attach the topic that kop created.

[codelipenghui]

Describe the bug Topic does not have schema to check when the function attach the topic that kop created.

To Reproduce Steps to reproduce the behavior:

1. publish some messages to kop topic
2. create a function and uses the above topic
3. see error "Topic does not have schema to check"

Expected behavior Pulsar function can consume messages from the topic that kop created.

[sijie]

I don't think we need to fix the issue here. People can create a function with a serde. So the function itself will not check the schema.