Incorrect reference for aonymous access

The text "(use `--anonymous`)" should read "(use `--allow-anonymous`)". --- #### Document Details ⚠ *Do not edit this section. It is required for learn.microsoft.com ➟ GitHub issue linking.* * ID: 7f2c02c4-8b2e-baa1-2930-190ea695d736 * Version Independent ID: 7f2c02c4-8b2e-baa1-2930-190ea695d736 * Content: [Dev tunnels security - Microsoft dev tunnels](https://learn.microsoft.com/en-us/azure/developer/dev-tunnels/security) * Content Source: [articles/dev-tunnels/security.md](https://github.com/MicrosoftDocs/azure-dev-docs/blob/main/articles/dev-tunnels/security.md) * Service: **azure-dev-tunnels** * GitHub Login: @curib * Microsoft Alias: **cauribeg**