Move UTC selection to testsuite environment variable

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

internal/app/wwctl/container/list/root.go

@@ -10,7 +10,6 @@ type variables struct {
 	kernel     bool
 	chroot     bool
 	compressed bool
-	utc        bool
 }
 
 // GetRootCommand returns the root cobra.Command for the application.
@@ -29,6 +28,5 @@ func GetCommand() *cobra.Command {
 	baseCmd.PersistentFlags().BoolVarP(&vars.size, "size", "s", false, "show size information")
 	baseCmd.PersistentFlags().BoolVarP(&vars.chroot, "chroot", "c", false, "show size of chroot")
 	baseCmd.PersistentFlags().BoolVar(&vars.compressed, "compressed", false, "show size of the compressed image")
-	baseCmd.PersistentFlags().BoolVarP(&vars.utc, "utc", "u", false, "use UTC for time output")
 	return baseCmd
 }