Fix Readiness check (#8681)

- Remove goroutine-check in Readiness check
- Bring in quorum check for readiness

Fixes #8385

Co-authored-by: Harshavardhana <harsha@minio.io>

cmd/gateway-unsupported.go

@@ -192,3 +192,8 @@ func (a GatewayUnsupported) IsEncryptionSupported() bool {
 func (a GatewayUnsupported) IsCompressionSupported() bool {
 	return false
 }
+
+// IsReady - No Op.
+func (a GatewayUnsupported) IsReady(_ context.Context) bool {
+	return false
+}