Review `new Function()` and `eval()` usage

## Bug Description

As highlighted by [a user in the support forums](https://wordpress.org/support/topic/plugin-fails-strict-csp-configurations/#post-18547519), review the plugin for any `new Function()` and `eval()` usage, so users can define more strict Content Security Policies.

The user who raised this highlighted the compiled vendor script in particular, `google-site-kit/dist/assets/js/googlesitekit-vendor-e44f66f****756bf1.js`.

From discussing this in an Engineering / Support sync, the issue may be from some of the plugin dependencies or how scripts are bundled.

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## Acceptance criteria

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## Implementation Brief

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## QA Brief

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## Changelog entry

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