[native] make SecondaryDeviceQRCodeScanner dismissible

Summary:
If you reject the Alert that pops up when you scan a QR code, the same alert will pop up if your phone camera is still pointed at the QR code. Instead, we should just go back when the cancel button is pressed.

https://linear.app/comm/issue/ENG-8935/cant-dismiss-secondarydeviceqrcodescanner

Test Plan: confirmed that if I press cancel on the Alert, I'm navigated back to the linked devices screen

Reviewers: ashoat

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D13036

native/profile/secondary-device-qr-code-scanner.react.js

@@ -316,8 +316,6 @@ function SecondaryDeviceQRCodeScanner(props: Props): React.Node {
     [processDeviceListUpdate],
   );
 
-  const onCancelScan = React.useCallback(() => setScanned(false), []);
-
   const handleBarCodeScanned = React.useCallback(
     (barCodeEvent: BarCodeEvent) => {
       setScanned(true);
@@ -328,7 +326,7 @@ function SecondaryDeviceQRCodeScanner(props: Props): React.Node {
           {
             text: 'Cancel',
             style: 'cancel',
-            onPress: onCancelScan,
+            onPress: goBack,
           },
           {
             text: 'Connect',
@@ -338,7 +336,7 @@ function SecondaryDeviceQRCodeScanner(props: Props): React.Node {
         { cancelable: false },
       );
     },
-    [onCancelScan, onConnect],
+    [goBack, onConnect],
   );
 
   if (hasPermission === null) {