Fixed regex bug in Safari (#89399)

* Fixed regex bug in Safari

* Added extra unit test

Author: thomheymann

x-pack/plugins/security/common/constants.ts

@@ -29,7 +29,7 @@ export const NEXT_URL_QUERY_STRING_PARAMETER = 'next';
  * - Must contain only letters, numbers, spaces, punctuation and printable symbols.
  * - Must not contain leading or trailing spaces.
  */
-export const NAME_REGEX = /^(?! )[a-zA-Z0-9 !"#$%&'()*+,\-./\\:;<=>?@\[\]^_`{|}~]+(?<! )$/;
+export const NAME_REGEX = /^(?! )[a-zA-Z0-9 !"#$%&'()*+,\-./\\:;<=>?@\[\]^_`{|}~]*[a-zA-Z0-9!"#$%&'()*+,\-./\\:;<=>?@\[\]^_`{|}~]$/;
 
 /**
  * Maximum length of usernames and role names.

x-pack/plugins/security/public/management/users/edit_user/create_user_page.test.tsx

@@ -88,6 +88,12 @@ describe('CreateUserPage', () => {
 
     await findAllByText(/Username must not contain leading or trailing spaces/i);
 
+    fireEvent.change(await findByLabelText('Username'), {
+      target: { value: 'username_with_trailing_space ' },
+    });
+
+    await findAllByText(/Username must not contain leading or trailing spaces/i);
+
     fireEvent.change(await findByLabelText('Username'), {
       target: { value: '€' },
     });