[WPB-9065] Stop supporting phone numbers in supported client API versions

[mdimjasevic]

Some golden tests have changed because support for phone-based account registration and activation has been disabled. The failure happens not when parsing a request body with a phone number, but rather at the endpoint handler level.

Twilio and Nexmo libraries have been dropped as they're dead code now.

Tracked by https://wearezeta.atlassian.net/browse/WPB-9065.

Checklist

• Grep "or phone" in the documentation and drop them
• Change the Stern API so that anything phone-related is removed
• Add a new entry in an appropriate subdirectory of changelog.d
• Read and follow the PR guidelines
• See if the "Phone/email whitelist" section of docs/src/developer/reference/user/activation.md should be modified
• Have golden tests for serializing users (Wire.API.User.User) that have a phone number in their identity (userIdentity) to JSON
• Check if there's an integration test for getting an activation code via email
• Fix unholy thing, i.e., using fail "error-code" and then changing the response in the middleware

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[mdimjasevic]

I started the PR so I can't approve it.

It all looks good to me.