fix: crash when registering with a registered email - WPB-14566 (#2224)

Co-authored-by: Christoph Aldrian <[email protected]>
Co-authored-by: Christoph Aldrian <[email protected]>

wire-ios-sync-engine/Source/Synchronization/Strategies/RegistationCredentialVerificationStrategy.swift

@@ -81,8 +81,11 @@ extension RegistationCredentialVerificationStrategy: ZMSingleRequestTranscoder {
                 error = NSError.invalidActivationCode(with: response) ??
                     NSError(userSessionErrorCode: .unknownError, userInfo: [:])
             default:
+                // We can end up here because more than one request can be sent for a single action/phase.
+                // This is an issue in some other part of SyncEngine but as a quick fix we will log and abort here.
                 let phaseString = registrationStatus.phase.map { "\($0)" } ?? "<nil>"
-                fatal("Error occurs for invalid phase: \(phaseString)")
+                WireLogger.authentication.error("Recieved unsuccessful response for invalid phase (\(phaseString))", attributes: .safePublic)
+                return assertionFailure("Error occurs for invalid phase: \(phaseString)")
             }
             registrationStatus.handleError(error)
         }