src/MPDeviceBleImpl.cpp: Fix compilation on GCC 14

GCC begins to get stricter regarding types in 14, meaning it will no longer allow casting a type int to const char*. This was fixed by simply casting the 0 to a char* with QByteArray::number(0). Is this the best way to go about it?

Gentoo bug: https://bugs.gentoo.org/916994

Error output:

src/MPDeviceBleImpl.cpp: In member function ‘QVector<QByteArray> MPDeviceBleImpl::processReceivedStartNodes(const QByteArray&) const’: src/MPDeviceBleImpl.cpp:738:18: error: invalid conversion from ‘int’ to ‘const char*’ [-fpermissive]
  738 |         return {0};
      |                  ^
      |                  |
      |                  int
In file included from /usr/include/qt5/QtCore/qstring.h:50,
                 from /usr/include/qt5/QtCore/qobject.h:47,
                 from /usr/include/qt5/QtCore/QObject:1,
                 from src/MPDevice.h:22,
                 from src/MPDeviceBleImpl.h:4,
                 from src/MPDeviceBleImpl.cpp:1:
/usr/include/qt5/QtCore/qbytearray.h:181:16: note:   initializing argument 1 of ‘QByteArray::QByteArray(const char*, int)’
  181 |     QByteArray(const char *, int size = -1);
      |                ^~~~~~~~~~~~

mooltipass / moolticute

src/MPDeviceBleImpl.cpp: Fix compilation on GCC 14 #1204