Proto: update delegate deactivation table with the actual last activity cycle

This MR updates the Delegate_last_cycle_before_deactivation table with the actual last activity cycle without doing any stitching during the protocol migration.

It means that the grace_period is off by:

• 2 cycles for the delegates with the last activity in the last cycle or last but one cycle of proto S
• 1 cycle for the delegates with the last activity in the first cycle of proto T

Why

This change is necessary for implementing the differentiated inactivity tolerance in !17582 (merged).

Manually testing the MR

dune exec tezt/tests/main.exe -- --file protocol_migration.ml -m "tolerated" --info

the protocol migration test is based on !16530 (merged)

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