[Security] Add ExpressionLanguage to require-dev.
minor #9778 [Security] Add ExpressionLanguage to require-dev. (realityking)

This PR was merged into the 2.4 branch.

Discussion
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[Security] Add ExpressionLanguage to require-dev.

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

Running the tests for Security-Core fails because ExpressionLanguage is missing.

Commits
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7f18d19 [Security] Add ExpressionLanguage to require-dev.