Use only lighthouse types in the mock builder (#4793)

## Proposed Changes

- only use LH types to avoid build issues
- use warp instead of axum for the server to avoid importing the dep

## Additional Info

- wondering if we can move the `execution_layer/test_utils` to its own crate and import it as a dev dependency
- this would be made easier by separating out our engine API types into their own crate so we can use them in the test crate
- or maybe we can look into using reth types for the engine api if they are in their own crate


Co-authored-by: realbigsean <seananderson33@gmail.com>

consensus/types/src/builder_bid.rs

@@ -21,7 +21,7 @@ pub struct BuilderBid<E: EthSpec, Payload: AbstractExecPayload<E>> {
     pub pubkey: PublicKeyBytes,
     #[serde(skip)]
     #[tree_hash(skip_hashing)]
-    _phantom_data: PhantomData<E>,
+    pub _phantom_data: PhantomData<E>,
 }
 
 impl<E: EthSpec, Payload: AbstractExecPayload<E>> SignedRoot for BuilderBid<E, Payload> {}

consensus/types/src/validator_registration_data.rs

@@ -21,3 +21,17 @@ pub struct ValidatorRegistrationData {
 }
 
 impl SignedRoot for ValidatorRegistrationData {}
+
+impl SignedValidatorRegistrationData {
+    pub fn verify_signature(&self, spec: &ChainSpec) -> bool {
+        self.message
+            .pubkey
+            .decompress()
+            .map(|pubkey| {
+                let domain = spec.get_builder_domain();
+                let message = self.message.signing_root(domain);
+                self.signature.verify(&pubkey, message)
+            })
+            .unwrap_or(false)
+    }
+}