Proto/Michelson: remove unused deprecated tx_rollup_l2_address type

Context

The TORU feature has been deactivated in Mumbai and no Michelson script using the tx_rollup_l2_address Michelson type has been originated on mainnet before Mumbai activation. We can hence safely remove the tx_rollup_l2_address type from the Michelson runtime and this is what this MR does.

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.
• Select as Assignee the next person who should take action on that MR