feat: adapt zksync_env_config::chain tests for running both in Validium mode and Rollup mode

[jordibonet-lambdaclass]

What ❔

Update the zksync_env_config::chain test of state_keeper_from_env to take into account the Rollup and Validium mode settings and check that both settings are modified correctly.

Checklist

• Adapt state keeper config for validium.
• Update the mock configuration for validium.

Changes

I have separated the expected_state_keeper_config() into two functions to manage the StateKeeperConfig for both modes and updated state_keeper_from_env() test to compare the new mockup configuration and the StateKeeperConfig of the Validium mode.

Check zksync_env_config::chain tests

zk test rust --package zksync_env_config --lib -j 1 -- chain::tests

[ilitteri]

This works fine. Let's refactor the code a little bit. I propose making expected_state_keeper_config generic for l1_batch_commit_data_generator_mode, and then we can either split the state_keeper_from_env test into a Validium and a Rollup one or just abstract the repeated logic into another helper function.

[ilitteri]

LGTM