…guesser is optional) (ogizanagi)This PR was merged into the 4.3 branch.Discussion----------[Serializer] Fix DataUriNormalizer deprecation (MIME type guesser is optional)| Q             | A| ------------- | ---| Branch?       | 4.3 <!-- see below -->| Bug fix?      | yes| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->| BC breaks?    | no     <!-- seehttps://symfony.com/bc -->| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->| Fixed tickets | N/A   <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        | N/ARelates to#31771 (comment) :The deprecation isn't fundamentally wrong, but if none of the Mime nor HttpFoundation components are installed, the DataUriNormalizer can be used, and the MIME type used will always be `'application/octet-stream'`https://github.com/symfony/symfony/blob/9691519ca46511005bc701ca93c2973923952034/src/Symfony/Component/Serializer/Normalizer/DataUriNormalizer.php#L39-L46https://github.com/symfony/symfony/blob/9691519ca46511005bc701ca93c2973923952034/src/Symfony/Component/Serializer/Normalizer/DataUriNormalizer.php#L135-L139So this completes the deprecation message, as well as allowing `null` again when no default MIME type guesser is available at all.Commits-------2740bd1 [Serializer] Fix DataUriNormalizer deprecation (MIME type guesser is optional)