Symfony version(s) affected

6.0.1

Description

Hi,

I am playing with Symfony 6 + PHP 8 on the Symfony Demo app, and wanted to test
https://symfony.com/blog/new-in-symfony-5-4-profiler-improvements#html-email-preview
(#43751)

I got this:

How to reproduce

1. Pull and boot https://github.com/symfony/demo app
2. Log in, go to a public blog post page at the bottom, and comment
3. See in the profiler > E-mails tab > HTML preview

Possible Solution

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Additional Context

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