Test that when the Adaptive Inflation activation vote reaches the threshold, the feature is set to launch

Context

This adds tests for !9058 (merged) on which this MR is stacked. This MR is stacked on !9061 (merged) and !9161 (merged) is stacked on this MR.

Manually testing the MR

dune exec src/proto_alpha/lib_protocol/test/integration/main.exe -- --file test_adaptive_inflation_launch.ml

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