Added new Forwarded header support for Request::getClientIps

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11073
| License       | MIT
| Doc PR        | no
Might be worth adding a test case for `Forwarded: For="[2001:db8:cafe::17]:4711"` returning `[2001:db8:cafe::17]:4711`. I don't think the current code handles it well. I also think it should preserve the [] for IPv6 as that is the common notation, but not sure if there are other precedents in symfony.