[FrameworkBundle] Added Crontoller::isCsrfTokenValid
feature #11602 [DX] [FrameworkBundle] Added Crontoller::isCsrfTokenValid (lyrixx)

This PR was merged into the 2.6-dev branch.

Discussion
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[DX] [FrameworkBundle] Added Crontoller::isCsrfTokenValid

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Commits
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479c833 [FrameworkBundle] Added Crontoller::isCsrfTokenValid