DAL/Tests: disable temporarily two tests

In the last three days

• dal node slot headers tracking failed 14 times
• dal attester with baker daemon failed 9 times

This MR suggests to disable them whilst work for fixing their flakiness goes on.

Follow-up from !14355 (merged)

What

Why

How

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• 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