The PHONE_NUMBER infoType functionality that was previously only available by setting InfoType.version to latest or stable is now also used when InfoType.version is set to legacy

## Change The `PHONE_NUMBER` [infoType](https://cloud.google.com/dlp/docs/infotypes-reference) functionality that was previously only available by setting [InfoType.version](https://cloud.google.com/dlp/docs/reference/rest/v2/InfoType) to `latest` or `stable` is now also used when [InfoType.version](https://cloud.google.com/dlp/docs/reference/rest/v2/InfoType) is set to `legacy`. The new model includes `US_TOLLFREE_PHONE_NUMBER` findings as type `PHONE_NUMBER` in the scan results. The old detection model that was previously available by setting [InfoType.version](https://cloud.google.com/dlp/docs/reference/rest/v2/InfoType) to `legacy` is no longer available.