[Twig Bridge] Fixed bug in ExpressionExtension

Currently it's impossible to use the expression extension in Twig as the <code> ExpressionExtension ::createExpression</code> method is defined as private which will throw an exception: <code>Fatal error: Call to private method Symfony\Bridge\Twig\Extension\ExpressionExtension::createExpression() from context '__TwigTemplate_83f94baa63f1faa30cdacee32980572936c887ef25baa389ebddd7a666db3a9b'</code>

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -