replace `navigator.userAgent` with `navigator.userAgentData`

[jodeleeuw]

Mainly needed for the browser-check plugin. navigator.userAgent is going to be less revealing soon, probably breaking the parsing that is in there.

• https://web.dev/user-agent-client-hints/
• https://developer.mozilla.org/en-US/docs/Web/API/Navigator/userAgentData
• https://developer.mozilla.org/en-US/docs/Web/API/User-Agent_Client_Hints_API

[alecgarza96]

https://github.com/jspsych/jsPsych/blob/main/packages/plugin-browser-check/src/index.ts

It appears here is where bulk of changes need to be made