Move HandleMalformedStrings middleware

What does this MR do and why?

This moves the HandleMalformedStrings middleware because in Rails 7 ActionableExceptions middleware is no longer loaded in production.

This is extracted from !90907 (merged) so the upgrade MR becomes smaller.

https://github.com/rails/rails/commit/779bc9987d9e94af2959e3903ee6a4976c00f3d4

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