Presence Status in Salesforce does not match with the Status in Genesys Cloud

When using Salesforce Voice (formerly Service Cloud Voice) with Genesys Cloud, the sfdc_phone service channel required for presence status mapping may be missing from the org. This channel is expected to be created automatically when Salesforce Voice is enabled.
The absence of the sfdc_phone service channel prevents proper presence status mapping between Salesforce and Genesys Cloud. The root cause is related to the timing of enabling Omni-Channel — if Omni-Channel is enabled before Salesforce Voice setup completes, the automatic channel creation may be skipped.