Fix passkey authentication submit method

Unfortunately, the submit and cancel form were unintentionally "merged" by migrating the `link_to` to `button_to`, overwriting the method for the regular login.

Regresses 0a38755

Author: MrSerth

app/views/webauthn_credential_authentication/_form.html.slim

@@ -1,6 +1,5 @@
-= form_tag(webauthn_credential_authentication_index_path, data: {public_key: @webauthn_get_options}, id: 'new_webauthn_credential_authentication')
-  .mb-3
+.actions.mt-3
+  = form_tag(webauthn_credential_authentication_index_path, data: {public_key: @webauthn_get_options}, id: 'new_webauthn_credential_authentication', class: 'd-inline-block')
     = hidden_field_tag('webauthn_credential[credential]', '')
-  .actions.mb-0
     = submit_tag(t('.verify_identity'), class: 'btn btn-primary me-2 mb-2')
-    = button_to(t('.cancel'), sign_out_path, method: :delete, class: 'btn btn-outline-secondary mb-2', data: {turbo: false})
+  = button_to(t('.cancel'), sign_out_path, method: :delete, form_class: 'd-inline-block', class: 'btn btn-outline-secondary mb-2', data: {turbo: false})