Description:
Currently, phone numbers configured as Fax-only do not appear in the "Called Number" selection when creating or editing Site-level Custom Rules (Site Call Handling) in the admin portal.

However, testing confirms that custom rules do successfully apply to fax traffic when the number is temporarily set to "Voice and Fax," added to the rule, and then reverted back to "Fax-only." This indicates that the backend supports fax interactions within custom rules, but the UI restricts selection based on number type.

Problem Statement:
This creates a usability gap where:

Fax-only numbers are not selectable in the UI
But are technically supported by the routing logic
Admins must perform a workaround (temporarily changing number type) to configure rules

Requested Enhancement:
Allow Fax-only numbers to be visible and selectable in the "Called Number" field when configuring Site Custom Rules, eliminating the need for temporary configuration changes.

Business Impact:

Improves admin experience and reduces confusion
Eliminates unnecessary configuration steps and potential misconfigurations
Aligns UI behavior with actual system capabilities
Supports environments where fax routing logic is required at the site level

Use Case:
Admins need to apply routing logic (via site custom rules) to numbers dedicated solely for fax without converting them to voice-enabled numbers.

Workaround (Current):

Change number type to "Voice and Fax"
Add number to custom rule
Revert number back to "Fax-only"

Expected Behavior:
Fax-only numbers should be directly selectable in custom rule configuration without requiring any temporary changes.