Pull request SiliconLabs#9: Update QRCode method

Merge in WMN_TOOLS/matter from fix_ci to silabs

Squashed commit of the following:

commit 784b59e8e9a20c4fb89266d8a06391a0bbb5640f
Author: jepenven-silabs <jean-francois.penven@silabs.com>
Date:   Tue Jul 5 14:33:59 2022 -0400

    Update QRCode method

silabs_examples/template/efr32/src/AppTask.cpp

@@ -275,11 +275,13 @@ CHIP_ERROR AppTask::Init()
 
 // Print setup info on LCD if available
 #ifdef DISPLAY_ENABLED
-    std::string QRCode;
+    // Create buffer for QR code that can fit max size and null terminator.
+    char qrCodeBuffer[chip::QRCodeBasicSetupPayloadGenerator::kMaxQRCodeBase38RepresentationLength + 1];
+    chip::MutableCharSpan QRCode(qrCodeBuffer);
 
     if (GetQRCode(QRCode, chip::RendezvousInformationFlags(chip::RendezvousInformationFlag::kBLE)) == CHIP_NO_ERROR)
     {
-        LCDWriteQRCode((uint8_t *) QRCode.c_str());
+        LCDWriteQRCode((uint8_t *) QRCode.data());
     }
     else
     {