Improve error message when Mime component is not installed

src/Symfony/Component/Validator/Constraints/FileValidator.php

@@ -173,7 +173,7 @@ public function validate($value, Constraint $constraint)
 
         if ($constraint->mimeTypes) {
             if (!class_exists(MimeTypes::class)) {
-                throw new LogicException('Validating mime types requires the "Mime" component. Install "symfony/mime" to use it.');
+                throw new LogicException('You cannot validate the mime-type of files as the Mime component is not installed. Try running "composer require symfony/mime".');
             }
 
             $mimeTypes = (array) $constraint->mimeTypes;