fix: Add method to check for WebKit WebView user agent string

[camdecoster]

Description

Adds utility method to check for WebKit WebView using user agent string. Closes #7476.

Changes

• Adds utility method
• Adds tests for user agent related methods

Testing

• TBD

Notes

• This change is necessary to enable logic when the library is being used in Plotly Studio
• The regex test returned the proper result for everything that I threw at it, but let me know if you find a breaking string
• An alternative (though narrower) approach is to test if the user is on a Mac and in a Tauri webview
  

[archmoj]

Great fix.
💃