use GlobalContext whenever possible (#9280)

This change is throughout the codebase to
ensure that all codepaths honor GlobalContext

cmd/web-handler-context.go

@@ -247,5 +247,5 @@ func newWebContext(r *http.Request, args ToKeyValuer, api string) context.Contex
 		BucketName:   bucket,
 		ObjectName:   object,
 	}
-	return logger.SetReqInfo(context.Background(), reqInfo)
+	return logger.SetReqInfo(GlobalContext, reqInfo)
 }