[JS render] Trusted-types for adaptivecards-designer

Part of the changes are drafted, and then reverted in #7819

• How to test designer change after you make trusted-types changes.

Edit the html directly from developer's tool provided by brower.

  <meta http-equiv="Content-Security-Policy" content="require-trusted-types-for 'script';" />

• Reference

TT docs: https://developer.mozilla.org/en-US/docs/Web/API/Trusted_Types_API
A Guide to TT: https://web.dev/trusted-types/
TT w3c spec: https://w3c.github.io/webappsec-trusted-types/dist/spec/

• Problem of adaptivecards-designer

fileNote.innerHTML =
            `By using the upload feature you agree to our <a href=${privacyLink} target='_blank'><span class='link'> image usage policy</span></a>`;

And possible fix

Start in the adaptivecards-designer JavaScript render path by locating the fileNote.innerHTML assignment shown in the issue. Add the CSP meta tag through browser developer tools to reproduce the Trusted Types failure, then verify that the upload notice renders correctly under the policy and that the relevant designer behavior remains functional.