Impl `From` between `fil_actors_shared::v{version}::runtime::Policy` types

**Issue summary**

Impl `From` between `fil_actors_shared::v{version}::runtime::Policy` types to address [this comment](https://github.com/ChainSafe/forest/pull/2983#discussion_r1244941274)

> It's not ideal. Theoretically, we could contrive a definition somewhere in fil-actor-states, see https://github.com/ChainSafe/forest/blob/devnet-in-ci/src/networks/mod.rs#L210
That being said, it's not important at the moment. Maybe we could have a tracking issue instead.

**Other information and links**

Start with the linked pull-request discussion and devnet-in-ci/src/networks/mod.rs around line 210 to understand the existing approach to versioned Policy values. Identify the relevant fil_actors_shared version modules and their tests, then verify that conversions between the Policy types compile and are covered by the project’s existing checks.

Written by the indexing model from the issue text.