matugen: fix app checking

- double nil for flatpak + bin required to skip

core/internal/utils/exec.go

@@ -5,6 +5,31 @@ import (
 	"strings"
 )
 
+type AppChecker interface {
+	CommandExists(cmd string) bool
+	AnyCommandExists(cmds ...string) bool
+	FlatpakExists(name string) bool
+	AnyFlatpakExists(flatpaks ...string) bool
+}
+
+type DefaultAppChecker struct{}
+
+func (DefaultAppChecker) CommandExists(cmd string) bool {
+	return CommandExists(cmd)
+}
+
+func (DefaultAppChecker) AnyCommandExists(cmds ...string) bool {
+	return AnyCommandExists(cmds...)
+}
+
+func (DefaultAppChecker) FlatpakExists(name string) bool {
+	return FlatpakExists(name)
+}
+
+func (DefaultAppChecker) AnyFlatpakExists(flatpaks ...string) bool {
+	return AnyFlatpakExists(flatpaks...)
+}
+
 func CommandExists(cmd string) bool {
 	_, err := exec.LookPath(cmd)
 	return err == nil