[JENKINS-74212] Extract inine JavaScript from BuildGraph/index.jelly

[yaroslavafenkin]

https://issues.jenkins.io/browse/JENKINS-74212

Other 25 violations that pop up in console in report-only mode of CSP plugin do not seem to affect the functionality. Everything seems to work just fine in restrictive mode.

I've tried to set ng-csp="no-unsafe-eval" on this line (ng-csp docs) but that had no visible effect on the number of violations. Nor on the functionality. Perhaps there are some features that I'm not aware of. My testing process is on the videos below.

Testing done

Before the change
After the change

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