[bug] auto generate desktop entry when start program

[Kiri2002]

In Archlinux, when launch imagej2, it will auto generate :

/home/kiri/.local/share/applications/ImageJ2.desktop

Contains:

[Desktop Entry]
Version=1.0
Name=ImageJ
GenericName=ImageJ
X-GNOME-FullName=ImageJ
Comment=Scientific Image Analysis
Type=Application
Categories=Education;Science;ImageProcessing;
Exec=/usr/share/imagej2/ImageJ-linux64 %F
TryExec=/usr/share/imagej2/ImageJ-linux64
Terminal=false
StartupNotify=true
MimeType=image/*;
Icon=/usr/share/imagej2/images/icon.png
StartupWMClass=net-imagej-launcher-ClassLauncher

If installed fiji, when start fiji, it will generate same name file, and contains:

[Desktop Entry]
Version=1.0
Name=ImageJ
GenericName=ImageJ
X-GNOME-FullName=ImageJ
Comment=Scientific Image Analysis
Type=Application
Categories=Education;Science;ImageProcessing;
Exec=/opt/fiji/ImageJ-linux64 %F
TryExec=/opt/fiji/ImageJ-linux64
Terminal=false
StartupNotify=true
MimeType=image/*;
Icon=/opt/fiji/images/icon.png
StartupWMClass=net-imagej-launcher-ClassLauncher

It may cause icon issues.
Any way to ban this aoto-generate behavior when building?

[ctrueden]

This desktop file autogeneration logic needs to be updated as part of the update to Java 21 + Jaunch. Intended behavior:

• never generate an ImageJ2.desktop anywhere
• generate only a Fiji.desktop in ~/.local/share/applications and maybe also in Fiji.app
• ensure the Fiji.desktop references the correct fiji-linux-<arch> executable
• ensure the Fiji.desktop includes the new fiji MIME type (Add support for fiji:// links fiji/fiji#343)
• ensure the Fiji.desktop references the Fiji icon, not the ImageJ2 icon
• update StartWMClass to org-scijava-launcher-ClassLauncher
• update the various name keys to use Fiji, not ImageJ nor ImageJ2
• include a comment linking to the source code that generates the file
• consider how to make the autogeneration optional, because the user might not want it—e.g. they may have multiple Fiji installations, which could fight over owning the icon