Update allergies.bats for wrong test case

[delvin2006v]

The problem tells to omit any score greater than 255 (where one has all the allergies). The last test case 509 however expects a list of allergies instead of "eggs". I have edited to only contain "eggs".

[github-actions]

This PR touches files which potentially affect the outcome of the tests of an exercise. This will cause all students' solutions to affected exercises to be re-tested.

If this PR does not affect the result of the test (or, for example, adds an edge case that is not worth rerunning all tests for), please add the following to the merge-commit message which will stops student's tests from re-running. Please copy-paste to avoid typos.

[no important files changed]

For more information, refer to the documentation. If you are unsure whether to add the message or not, please ping @exercism/maintainers-admin in a comment. Thank you!

[delvin2006v]

@exercism/maintainers-admin This commit affects the test file and all the runs by all users.

[IsaacG]

1. https://exercism.org/docs/community/being-a-good-community-member/suggesting-exercise-improvements. These tests are generated from the upstream canonical data. Manual edits to this file will be overwritten and are not accepted.
2. Have you discussed this issue with anyone? 509 = 256 (ignored) + 128 (cats) + 64 (pollen) + 32 (chocolate) + 16 (tomatoes) + 8 (strawberries) + 4 (shellfish) + 1 (eggs) so the allergy list is correct.

[delvin2006v]

Sorry, now I understood the whole question.