Fix mc_project_version_delete() return value

The function's return type does not match the WSDL definition.

This is a regression introduced by a80f447
which changed version_delete()'s return type from true (bool) to void
Since mc_project_version_delete() actually returned that, it causes a
side effect because void == NULL == false.

To avoid an unnecessary and potentially breaking change in the WSDL, the
function now returns true.

Fixes #25856

(cherry picked from commit 5039c7b)

api/soap/mc_project_api.php

@@ -618,7 +618,8 @@ function mc_project_version_delete( $p_username, $p_password, $p_version_id ) {
 		return mci_soap_fault_access_denied( $t_user_id );
 	}
 
-	return version_remove( $p_version_id );
+	version_remove( $p_version_id );
+	return true;
 }
 
 /**