fix: background heal to call HealFormat only if needed (#9491)

In large setups this avoids unnecessary data transfer
across nodes and potential locks.

This PR also optimizes heal result channel, which should
be avoided for each queueHealTask as its expensive
to create/close channels for large number of objects.

pkg/madmin/heal-commands.go

@@ -45,6 +45,20 @@ type HealOpts struct {
 	ScanMode  HealScanMode `json:"scanMode"`
 }
 
+// Equal returns true if no is same as o.
+func (o HealOpts) Equal(no HealOpts) bool {
+	if o.Recursive != no.Recursive {
+		return false
+	}
+	if o.DryRun != no.DryRun {
+		return false
+	}
+	if o.Remove != no.Remove {
+		return false
+	}
+	return o.ScanMode == no.ScanMode
+}
+
 // HealStartSuccess - holds information about a successfully started
 // heal operation
 type HealStartSuccess struct {