test(email-templates): align token assertions with current dot-notation tokens 🤖

[mrjbj]

What changes I've made

AI noticed that certain tests were failing on develop branch due to code refactoring from snake_case to dot.notaion in EmailTemplageTokenTest This patch updates those tests.

EmailTemplateTokenTest asserts old underscore-style token names ({{ order_first_name }}, {{ attendee_name }}, {{ event_title }}, {{ order_number }}, {{ order_total }}, {{ organizer_name }}, {{ order_last_name }}) but
LiquidTemplateRenderer::getAvailableTokens has been emitting dot-notation tokens ({{ order.first_name }}, {{ attendee.name }}, {{ event.title }}, etc.) since the format was refactored. The test was never updated, so 3 of its 6 cases have been failing
on develop for a while:

• test_can_get_order_confirmation_tokens (asserts {{ order_first_name }} exists)
• test_can_get_attendee_ticket_tokens (asserts {{ attendee_name }} exists)
• test_tokens_include_order_specific_tokens (asserts {{ event_title }} etc. exist)

This PR updates the assertions to match the actual emitted tokens. No production code change — purely test alignment.

How I've tested these changes

• php artisan test --filter=EmailTemplateTokenTest — 6 passed (was 3 failed)

Checklist

• I have read the contributing guidelines.
• My code follows the coding standards of the project.
• I have tested my changes, and they work as expected.
• I understand that this PR will be closed if I do not follow the contributor guidelines and if this PR template is left unedited.