Scan passport once (#935)

StripeIdentity/StripeIdentity/Source/NativeComponents/ViewControllers/DocumentCaptureViewController.swift

@@ -562,7 +562,12 @@ extension DocumentCaptureViewController: AVCaptureVideoDataOutputSampleBufferDel
 @available(iOSApplicationExtension, unavailable)
 extension DocumentCaptureViewController: IdentityDataCollecting {
     var collectedFields: Set<VerificationPageFieldType> {
-        return Set([.idDocumentFront]).union(documentType.hasBack ? [.idDocumentBack] : [])
+        // Note: Always include the document back, even if the document type
+        // doesn't have a back. The initial VerificationPage request is made
+        // before the user selects which document type they've selected, so it
+        // will always include the back. Including `idDocumentBack` here ensures
+        // that the user isn't erroneously prompted to scan their document twice.
+        return [.idDocumentFront, .idDocumentBack]
     }
 }