QR Scanner Sometimes Returns an Error from Sparrow

`Can't find matching app for this request:`

I discovered this in a strange way. First I was doing a CPFP transaction and got this error, followed by a long binary string. I tried RBF instead and Specter-DIY was able to sign without issues.

Then today I tried a new transaction that is a 1 input 1 output `p2wsh` transaction and I got the error again. Sometimes the error is an empty string, sometimes it's a long binary string. At first it seemed like selecting `decrease density` on Sparrow caused an empty string, but now it's happening both ways.

Or sometimes it returns this memory allocation error (I deleted the other wallets on this device and restarted to see if that made a difference):

IIRC I only get the memory allocation error when using decreased density.

Reproduce the QR scanner failure from Sparrow using CPFP, RBF, and the 1-input/1-output p2wsh transaction, testing both density settings. Compare the empty, binary-string, and memory-allocation failures and trace the QR decoding and memory-allocation paths. Done means these transaction types scan reliably without errors.

Written by the indexing model from the issue text.