minor #22049 [Security] simplify the SwitchUserListenerTest (xabbuh)
minor #22049 [Security] simplify the SwitchUserListenerTest (xabbuh)

This PR was merged into the 2.7 branch.

Discussion
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[Security] simplify the SwitchUserListenerTest

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

While working on #22048 I noticed that the `SwitchUserListenerTest` was more complicated than necessary by mocking a lot of stuff that didn't need to be mocked.

Commits
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923bbdbf9f [Security] simplify the SwitchUserListenerTest

symfony/security-http