Etherlink: completely remove the option to enable or disable hot/cold accesses

Context

Follow-up from !17349 (merged).

By default the option will be activated.

Now that MR !15812 (merged) has been merged into master, we can completely remove the enable_warm_cold_access parameter to better align gas consumption with the actual execution. This should also help @thomas.plisson in his quest to remove the tick model.

Data

Etherlink - Gas consumption with or without hot/cold enabled

On average we consume 0.63% more gas.