prevent setting typeClassName to `[B` when runtime could inferring the typeClassName

[freeznet]

#131 added the inferring typeClassName feature to Pulsar Functions Java runtime, but the webhook prevents the user from providing null to typeClassName. We will need to fix it by removing the webhook Defaulter to enable the new feature for Function Mesh users.

[jiangpengcheng]

which version(tag) does the java runtime image introduce this feature?

we may need to keep the webhook for old image

[freeznet]

@jiangpengcheng I do not have the specific image tags containing the fix, but you could check apache/pulsar#18111 and streamnative/pulsar fork