[JENKINS-74435] Extract inline JS script and legacy onClick handlers in ElectricflowPipelinePublisher/config.jelly

[shlomomdahan]

https://www.jenkins.io/doc/developer/security/csp/

JENKINS-74435

This PR was created to extract the inline JS and legacy onClick handlers in ElectricflowPipelinePublisher/config.jelly.

Testing done

Waiting to test until I can run Kubernetes cluster locally.

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