[pulsar-function] fix possible deadlock on broker-function service startup #9499
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Motivation
Standalone pulsar broker and function service can have deadlock which also sometime causes failures in function unit-test case. Pulsar function tries to create a subscription which blocks the zk thread and can be cause of possible deadlock. Below is the thread-dump when the deadlock happens and function service start up fails.
So, remove blocking call while creating subscription using admin-api.