feat: added supportsRTCPeerConnection()

[marcin-bazyl]

Description

Added API for checking if RTCPeerConnection is available - needed because some browser extensions remove it from window object and we need to show a tailored error UI for those users.

This change implements...

• A new feature
• A bug fix
• Other (please specify):

Is this a breaking change?

• Yes
• No

I certify that...

• All relevant unit and integration tests have passed and/or have been updated according to this change.

Generative AI (GAI) Usage Disclosure

Reference: Cisco GAI Coding Guidelines

• Cisco approved GAI tool/IDE was used for coding - eg: VSCode, Cursor, Windsurf, Codex, Claude code
• No GAI - Code was written entirely manually without GAI assistance

If a GAI tool/IDE was used then select the category that best describes GAI usage in this PR:

• Manual Draft with GAI Refinement - I/we created a draft manually that was non-substantively modified by GAI (e.g., refactoring was performed by GAI on manually written code) (Default)
• GAI Draft with Manual Customization - GAI tool was used to create a draft that I/we subsequently customized or modified.
• GAI Generated Code - Code was generated entirely by GAI

Additional GAI Usage Details (Optional):

[bbaldino]

Do we want to frame this as a "isWebRtcSupported" check? I.e. that we might potentially expand in the future to check for things other than just peer connection?