Replace the bundled ReadableStream polyfill with the `web-streams-p…

…olyfill` npm package (issue 11157)

Compared to the recently replaced `URL` polyfill, the new `ReadableStream` polyfill isn't being exported globally for two reasons:
 - We're currently checking for the existence of a global `ReadableStream` implementation when determining if the Fetch API will be used; please see `isFetchSupported` in the src/display/display_utils.js file.
 - Given that it's much newer functionality (compared to `URL`) and that not all browsers may implement all parts of the specification yet, not exposing the `ReadableStream` globally seems safer for now.

.eslintignore

@@ -7,7 +7,6 @@ external/webL10n/
 external/cmapscompress/
 external/builder/fixtures/
 external/builder/fixtures_esprima/
-external/streams/
 src/shared/cffStandardStrings.js
 src/shared/fonts_utils.js
 test/tmp/

.eslintrc

@@ -115,10 +115,6 @@
         "name": "ReadableStream",
         "message": "Import it from `src/shared/util.js` or `pdfjsLib` instead; outside of the `/src` and `/web` folders, the rule may be disabled as needed. ",
       },
-      {
-        "name": "WritableStream",
-        "message": "Import it from `src/shared/util.js` or `pdfjsLib` instead; outside of the `/src` and `/web` folders, the rule may be disabled as needed. ",
-      },
     ],
     "no-shadow-restricted-names": "error",
     "no-shadow": "off",