Revert "Change cursortheme installpath from ~/.icons to XdgTargetDir/icons"

This reverts commit e26425e573.

The KCM does not always include the install folder in the search paths.

As discussed in https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/1233, a revert is
the best option for the time being.

BUG: 453765


(cherry picked from commit ad4a9bd093)

kcms/cursortheme/xcursor/xcursor.knsrc

@@ -45,7 +45,7 @@ Name[x-test]=xxCursorsxx
 Name[zh_CN]=光标
 
 Categories=X11 Mouse Theme
-TargetDir=icons
+InstallPath=.icons
 Uncompress=always
 RemoveDeadEntries=true
 AdoptionCommand=plasma-apply-cursortheme %f