Check compliance with Trusted Types

[sosnovsky]

Google announced that they extend Trusted Types to Gmail in mid-February - https://workspaceupdates.googleblog.com/2024/01/extending-trusted-types-to-gmail.html:

This new enforcement mode will require third-party extensions to use typed objects instead of strings when assigning values to DOM APIs. Once Trusted Types are fully enforced, the Trusted Types directive will be present in the Content Security Policy (CSP) header:
Content-Security-Policy: require-trusted-types-for 'script';report-uri https://mail.google.com/mail/cspreport

We already use DOMPurify library for DOM manipulations, but need to re-check if extension is fully complaint with Trusted Types.