fix: use install_with_observer for B20Factory/PolicyRegistry precompiles

[stephancill]

Motivation

base/base's fork-test CI (base-std-fork-tests.yml) patches the local precompile crates into the pinned base-anvil and rebuilds anvil/forge. It now fails to compile on every base/base PR:

error[E0599]: no function or associated item named `install` found for struct `B20Factory`
error: could not compile `foundry-evm-networks`

base/base dropped the plain install() shims for B20Factory and PolicyRegistryPrecompile in favour of the observed variants (only install_with_observer remains). Our inject_precompiles still called the removed B20Factory::install / PolicyRegistryPrecompile::install.

Solution

• Switch both to install_with_observer with a NoopPrecompileCallObserver, matching provider.rs. Observation is scoped to the B-20 token call path (which anvil doesn't wire up), so a no-op observer is correct.
• B20Factory::install_with_observer(precompiles, upgrade, observer) also takes a BaseUpgrade, so thread Beryl through like the lookup (ActivationRegistry::install and BerylLookup::install are unchanged and kept).
• Bump the base/base pin 401ffe4d → cc8ee38 (current main) so this crate compiles against the observer-only API.

Verified: cargo check -p foundry-evm-networks compiles clean against main.

Context

Follows #50 (which threaded BaseUpgrade into the B-20 lookup). This is the same class of base/base API drift; addresses the newer removal of the plain install shims.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes