Remove license header from third-party code

Summary:
The `flow-typed/npm` path contains third-party code. The propietary Facebook license header should not be included in these files.

Changelog: [Internal]

Reviewed By: fkgozali

Differential Revision: D24082894

fbshipit-source-id: 34928c7a6a3d1fdf8d91b4cdd86eb72ca6341545

Author: hramos

flow-typed/npm/base64-js_v1.x.x.js

@@ -1,6 +1,4 @@
 /**
- * (c) Facebook, Inc. and its affiliates. Confidential and proprietary.
- *
  * @flow strict
  * @format
  */

flow-typed/npm/pretty-format_v26.x.x.js

@@ -1,6 +1,4 @@
 /**
- * (c) Facebook, Inc. and its affiliates. Confidential and proprietary.
- *
  * @flow strict
  * @format
  */

flow-typed/npm/promise_v8.x.x.js

@@ -1,6 +1,4 @@
 /**
- * (c) Facebook, Inc. and its affiliates. Confidential and proprietary.
- *
  * @flow strict
  * @format
  */

flow-typed/npm/prop-types_v15.x.x.js

@@ -1,9 +1,4 @@
 /**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
  * @flow strict
  * @nolint
  * @format

flow-typed/npm/react-dom_v16.x.x.js

@@ -1,7 +1,4 @@
 /**
- * Copyright (c) 2013-present, Facebook, Inc.
- * All rights reserved.
- *
  * react-dom v16.x.x libdefs from flow-typed
  *
  * @noformat

flow-typed/npm/stacktrace-parser_v0.1.x.js

@@ -1,6 +1,4 @@
 /**
- * (c) Facebook, Inc. and its affiliates. Confidential and proprietary.
- *
  * @flow strict
  * @format
  */