Circuit display shows WebTunnel placeholder IPv6 address

🐞 Bug Report

The Tor Browser circuit display incorrectly shows a WebTunnel IPv6 placeholder address (or even a spoofed address). While this isn't a major issue, it can be misleading for Tor users.

Reproduction steps

1. Go to bridges.torproject.org
2. Copy a webtunnel bridge line.
3. In TB, go to Connection about:preferences#connection and paste the bridge line.
4. Check the Circuit Display

Now, if you edit the bridge line and replace the IP address with a random one (e.g., 8.8.8.8), the circuit display will show that you are connected to 8.8.8.8.

Expected behavior

Since WebTunnel bridge IPv6 addresses are reserved for documentation and not actually used, Tor Browser should display only the WebTunnel domain or simply "WebTunnel." The circuit display should not show any IP address for this PT.

Actual behavior

The circuit display is currently showing a misleading IPv6 address as part of the user circuit.

Bookkeeping

• Browser version: 14.5.4
• Browser channel:
  • Release
  • Alpha
  • Nightly
• Distribution method:
  • Installer/archive from torproject.org
  • tor-browser-launcher
  • homebrew
  • other (please specify):
• Operating System:
  • Windows
  • macOS
  • Linux
  • Android
  • Tails
  • Other (please specify):

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