[JENKINS-76310] Make secret token work with CSP enforced

[daniel-beck]

https://issues.jenkins.io/browse/JENKINS-76310

Depends on jenkinsci/jenkins#20345

Draft due to dependency on incremental, once the core change is in a weekly release I'll update this.

Testing done

Manually navigated to the buttons and clicked them, checked CSP findings -- none. Work when CSP is enforced.

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