Tezt: revamp test on mempool config operation filtering

Context

Revamp the tezt test on the effect of the mempool config on incoming operations.

Fixes an item of #5541 (closed)

Manually testing the MR

dune exec tezt/tests/main.exe -- node mempool filter arrival -i

Checklist

• [N/A] Document the interface of any function added or modified (see the coding guidelines)
• [N/A] Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• [N/A] For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR