Compatibility with qt6-online-installer

[tresf]

When using linuxdeploy-plugin-qt with Qt6 installed from the qt6-online-installer, it fails with the following message:

ERROR: Could not find dependency: libQt6Xml.so.6 
ERROR: Failed to deploy dependencies for existing files 

ldd on the main executable shows the correct path:

tresf@ubuntu-linux-2404:~/lmms/build$ ldd lmms
	linux-vdso.so.1 (0x0000e3d32ffce000)
	libQt6Widgets.so.6 => /home/tresf/Qt/6.8.2/gcc_arm64/lib/libQt6Widgets.so.6 (0x0000e3d32ec00000)
	libQt6Xml.so.6 => /home/tresf/Qt/6.8.2/gcc_arm64/lib/libQt6Xml.so.6 (0x0000e3d32ff40000)
	libQt6Gui.so.6 => /home/tresf/Qt/6.8.2/gcc_arm64/lib/libQt6Gui.so.6 (0x0000e3d32e000000)

Workaround:

A temporary workaround is to set LD_LIBRARY_PATH to ~/Qt/6.8.2/gcc_arm64/lib/

Environment:

• OS: Ubuntu 24.04
• Arch: ARM64
• Qt: 6.8.2
• linuxdeploy: version 1-alpha (git commit ID c28054b), GitHub actions build 303 built on 2025-02-13 18:15:04 UTC
• linuxdeploy-plugin-qt: version 1-alpha (git commit ID ce5291e), GitHub actions build 210 built on 2025-02-13 21:29:12