Proto: Refine initial value of [reveal_activation_level]

Context

The stitching to Oxford is a bit buggy wrt. the DAL feature flag. It is not a very important issue, but to prepare the stitching from Oxford, we fix the inconsistency.

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.
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