Make the container considered non-fresh if the environment parameters are changed

| Q             | A
| ------------- | ---
| Bug fix?      | not really
| New feature?  | kind of
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11365
| License       | MIT
| Doc PR        | https://github.com/symfony/symfony-docs/pull/4645

Fixes #11365 by making the container non-fresh if any of the prefixed environment parameters are added/removed/changed. Not a bug as it was documented as behaving as such, but I think it's worth applying to 2.3 rather than considering it a new feature.
why is this ksort needed here?