Issue #3497460: Removes client side cruft.

Closes #3497460

js/alt_text_validation.es6.js

-/**
- * @file
- * Attaches behaviors VA GOv Media module.
- */
-(($, Drupal, once, drupalSettings) => {
-  if (typeof drupalSettings.cvJqueryValidateOptions === "undefined") {
-    drupalSettings.cvJqueryValidateOptions = {};
-  }
-
-  if (drupalSettings.clientside_validation_jquery.force_validate_on_blur) {
-    drupalSettings.cvJqueryValidateOptions.onfocusout = (element) => {
-      // "eager" validation
-      this.element(element);
-    };
-  }
-
-  drupalSettings.cvJqueryValidateOptions.rules = {
-    "image[0][alt]": {
-      remote: {
-        url: `${drupalSettings.path.baseUrl}media/validate`,
-        type: "post",
-        data: {
-          value() {
-            return $("textarea[data-drupal-selector='edit-image-0-alt']").val();
-          },
-        },
-        dataType: "json",
-      },
-    },
-    "media[0][fields][image][0][alt]": {
-      remote: {
-        url: `${drupalSettings.path.baseUrl}media/validate`,
-        type: "post",
-        data: {
-          value() {
-            return $(
-              "textarea[data-drupal-selector='edit-media-0-fields-image-0-alt']"
-            ).val();
-          },
-        },
-        dataType: "json",
-      },
-    },
-  };
-
-  // Add messages with translations from backend.
-  $.extend(
-    $.validator.messages,
-    drupalSettings.clientside_validation_jquery.messages
-  );
-
-  /**
-   * Attaches jQuery validate behavior to forms.
-   *
-   * @type {Drupal~behavior}
-   *
-   * @prop {Drupal~behaviorAttach} attach
-   *  Attaches the outline behavior to the right context.
-   */
-  Drupal.behaviors.altTextValidate = {
-    // eslint-disable-next-line no-unused-vars
-    attach(context) {
-      // Allow all modules to update the validate options.
-      // Example of how to do this is shown below.
-      $(document).trigger(
-        "cv-jquery-validate-options-update",
-        drupalSettings.cvJqueryValidateOptions
-      );
-
-      // Process for all the forms on the page everytime,
-      // we already use once so we should be good.
-      once("altTextValidate", "body form").forEach((element) => {
-        $(element).validate(drupalSettings.cvJqueryValidateOptions);
-      });
-    },
-  };
-  // eslint-disable-next-line no-undef
-})(jQuery, Drupal, once, drupalSettings);