DEV: Admin webhooks interface issues (#19360)

1. The events table had broken styling, making each row overflow
2. It had confusing routes: `/:id` for "edit" and `/:id/events` for "show" (now it's `/:id/edit` and `/:id` respectively)
3. There previously was an unused backend action (`#edit`) - now it is used (and `web_hooks/:id/events` route has been removed)
4. There was outdated/misplaced/duplicated CSS
5. And more

app/assets/javascripts/admin/addon/controllers/admin-web-hooks-index.js

@@ -0,0 +1,36 @@
+import Controller, { inject as controller } from "@ember/controller";
+import I18n from "I18n";
+import { popupAjaxError } from "discourse/lib/ajax-error";
+import { inject as service } from "@ember/service";
+import { action } from "@ember/object";
+import { alias } from "@ember/object/computed";
+
+export default Controller.extend({
+  adminWebHooks: controller(),
+  dialog: service(),
+  contentTypes: alias("adminWebHooks.contentTypes"),
+  defaultEventTypes: alias("adminWebHooks.defaultEventTypes"),
+  deliveryStatuses: alias("adminWebHooks.deliveryStatuses"),
+  eventTypes: alias("adminWebHooks.eventTypes"),
+  model: alias("adminWebHooks.model"),
+
+  @action
+  destroy(webhook) {
+    return this.dialog.deleteConfirm({
+      message: I18n.t("admin.web_hooks.delete_confirm"),
+      didConfirm: async () => {
+        try {
+          await webhook.destroyRecord();
+          this.model.removeObject(webhook);
+        } catch (e) {
+          popupAjaxError(e);
+        }
+      },
+    });
+  },
+
+  @action
+  loadMore() {
+    this.model.loadMore();
+  },
+});