Validator fails to detect lack of required amp-access-scroll extension script

## What's the issue?

If a site using `amp-access` adds an integration to the Scroll network, it is required to load the `amp-access-scroll` extension script ([see docs](https://amp.dev/documentation/components/amp-access-scroll/)).

However, the validator does not detect this issue as it is missing a rule to recognize this use case. This is clearly an invalid AMP page, though, as the functionality it is trying to use is broken if that dependency is missing.

This also means that the `auto-extensions` transformer in the NodeJS and PHP toolbox packages will not properly add the required `amp-access-scroll` extension script automatically, leading to a broken page.

Related issue: https://github.com/ampproject/amp-wp/issues/5999

## How do we reproduce the issue?

Here's a playground example which should throw a validation error, as the required `amp-access-scroll` extension script is not loaded even though it is being used by the markup: [Playground example](https://playground.amp.dev/#share=<!-- ## Introduction
  The [amp-access](/content/amp-dev/documentation/components/reference/amp-access-v0.1.md) component adds support for authentication and authorization, allowing you to limit access to parts of your AMP pages as well as display customized content for the logged in user.  It also allows the implementation of view counting, paywalls and subscriptions. For sample `amp-access` server endpoints, see the [amp-publisher-sample](https://github.com/ampproject/amp-publisher-sample) project.
--><!-- -->
<!doctype html>
<html ⚡ lang="en">
<head>
<meta charset="utf-8">
  <title>amp-access</title>
  <script async src="https://cdn.ampproject.org/v0.js"></script>

  <!-- ## Setup -->
  <!-- Import the `amp-access` component in the header. -->
  <script async custom-element="amp-access" src="https://cdn.ampproject.org/v0/amp-access-0.1.js"></script>
  <!-- `amp-access` requires `amp-analytics` to be imported as well. -->
  <script async custom-element="amp-analytics" src="https://cdn.ampproject.org/v0/amp-analytics-0.1.js"></script>

  <!-- Optionally, use the [`amp-mustache`](/content/amp-dev/documentation/components/reference/amp-mustache-v0.2.md) component to show text with values replaced from the authorization response -->
  <script async custom-template="amp-mustache" src="https://cdn.ampproject.org/v0/amp-mustache-0.2.js"></script>

  <!-- Add the configuration for the `authorization` and the `login` endpoints. We provide two login endpoints, one for sign-in and one for sign-out. It is also possible to create a fallback response that will be used if the authorization fails with the `authorizationFallbackResponse` attribute.

    The [Pingback Endpoint](/content/amp-dev/documentation/components/reference/amp-access.md#pingback-endpoint) is called when a user views the document, which can be used to update metering information. This functionality is not used in this sample.
  -->
  <script id="amp-access" type="application/json">
    {
        "authorization": "/documentation/examples/api/amp-access/authorization?rid=READER_ID&url=CANONICAL_URL&ref=DOCUMENT_REFERRER&_=RANDOM",
        "pingback": "/documentation/examples/api/amp-access/pingback?rid=READER_ID&url=CANONICAL_URL&ref=DOCUMENT_REFERRER&_=RANDOM",
        "login": {
          "sign-in": "/documentation/examples/api/amp-access/login?rid=READER_ID&url=CANONICAL_URL",
          "sign-out": "/documentation/examples/api/amp-access/logout"
        },
        "authorizationFallbackResponse": {
            "error": true,
            "loggedIn": false,
            "powerUser": false
        },
		"vendor": "scroll",
		"namespace": "scroll"
    }
  </script>
  <link rel="canonical" href="https://amp.dev/documentation/examples/components/amp-access/index.html">
  <meta name="viewport" content="width=device-width">
  <style amp-boilerplate>body{-webkit-animation:-amp-start 8s steps(1,end) 0s 1 normal both;-moz-animation:-amp-start 8s steps(1,end) 0s 1 normal both;-ms-animation:-amp-start 8s steps(1,end) 0s 1 normal both;animation:-amp-start 8s steps(1,end) 0s 1 normal both}@-webkit-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}</style><noscript><style amp-boilerplate>body{-webkit-animation:none;-moz-animation:none;-ms-animation:none;animation:none}</style></noscript>
</head>
<body>

  <!-- ## Controlling visibility -->
  <!-- This section is visible to all users. No special markup is needed in this case.-->
  <section>
    Welcome to the website! This section is visible to all.
  </section>

   <!-- Use the `amp-access` attribute to control the visibility of each component. The expression must evaluate to a boolean value. If it evaluates to `TRUE`, the section will be shown.

    We use the `loggedIn` property from the server's response to determine whether the user is logged in.
  -->
  <section amp-access="loggedIn">
    This section is only visible if you're logged in. Welcome back!
  </section>

  <!-- The response from the server can be used to convey more information about the logged in user. In this case, we differentiate between users who have the `powerUser` property set in addition to being logged in.
  -->
  <section amp-access="loggedIn AND powerUser">
    This section is only visible if you're logged in <em>and</em> classified as "power user".
  </section>

  <!-- If the `loggedIn` property has the default value of false, we can assume that the user is not logged in.
   -->
  <section amp-access="NOT loggedIn">
    This section is only visible if you're not logged in.
  </section>

  <!-- Combine `amp-access` and `amp-mustache` to show information returned from the authorization request. In this case we show the email returned in the authentification response.
  -->
  <section amp-access="loggedIn">
    <template amp-access-template type="amp-mustache">
      <h3>Hello {{email}}!</h3>

      {{#powerUser}}
      <p>You are a power user.</p>
      {{/powerUser}}
    </template>
  </section>

  <!-- ## Login  -->
  <!-- Use `on="tap:amp-access.login-sign-in"` to open the login dialog when the element is clicked. This simply opens a popup window that takes the user to the URL defined inside the configuration at the top. `amp-access-hide` will default the component to be hidden and enabled later if the `amp-access` expression is evaluated to `TRUE` -->
  <button amp-access="NOT loggedIn" amp-access-hide on="tap:amp-access.login-sign-in">
    Login
  </button>

  <!-- ## Logout  -->
  <!-- The logout link should only be shown for logged in subscribers. We use a trick here: the logout is a login action that directly redirects back to the original URL. This has the advantage that the page updates without being reloaded.
  -->
  <button amp-access="loggedIn" amp-access-hide on="tap:amp-access.login-sign-out">
    Logout
  </button>
  <!-- Check out the [official amp-access sample](https://rocky-sierra-1919.herokuapp.com/) for demos of first-click-free and view counting. -->

  <section amp-access="NOT scroll.scroll">
    This is only shown when user not identified as member of the Scroll network.
  </section>
</body></html>)

Start with the linked AMP Playground example and reproduce the missing validation error for an amp-access configuration using the Scroll vendor. Then trace the validator rule and the auto-extensions behavior in the NodeJS and PHP toolbox packages; done means the validator reports the missing amp-access-scroll script and both toolboxes add it automatically.

Written by the indexing model from the issue text.