fix(admin): sanitize fediverse username (#3437)

* test: add config federation test

* fix: santize fediverse username

fixes #3424

* refactor: remove commented code

* refactor: change username const to usernameValue

* refactor: use shorthand property

* build: move stories page out of build directory

* fix: allow only alphanumeric chars in username

* fix: filter out special chars in username

Added a regex filter to strip non-alphanumeric chars in username field.

* chore: clean unused fields

web/stories/config-federation.stories.tsx

@@ -0,0 +1,16 @@
+import { Meta } from '@storybook/react';
+import ConfigFederation from '../pages/admin/config-federation';
+
+const meta = {
+  title: 'owncast/Admin/Config/Federation',
+  component: ConfigFederation,
+  parameters: {},
+} satisfies Meta<typeof ConfigFederation>;
+
+export default meta;
+
+const Template = arguments_ => <ConfigFederation {...arguments_} />;
+
+export const Default = Template.bind({});
+
+Default.args = {};