fix: trigger heal if one of the parts are not found (#11358)

Previously we added heal trigger when bit-rot checks
failed, now extend that to support heal when parts
are not found either. This healing gets only triggered
if we can successfully decode the object i.e read
quorum is still satisfied for the object.

pkg/madmin/heal-commands.go

@@ -31,8 +31,12 @@ import (
 type HealScanMode int
 
 const (
+	// HealUnknownScan default is unknown
+	HealUnknownScan HealScanMode = iota
+
 	// HealNormalScan checks if parts are present and not outdated
-	HealNormalScan HealScanMode = iota
+	HealNormalScan
+
 	// HealDeepScan checks for parts bitrot checksums
 	HealDeepScan
 )