Use regex to check whether runner image has pulsarctl

[jiangpengcheng]

Motivation

Some runner images(such as pulsar-functions-sn-java-runner) may has pulsarctl in /pulsar/bin dir, but we are using /usr/local/bin/pulsarctl as the pulsarctl path, so it's better to use pulsarctl directly and add /pulsar/bin to the $PATH

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