Remove safe_arith and import from crates.io (#8191)

Use the recently published `safe_arith` and remove it from Lighthouse
https://crates.io/crates/safe_arith


Co-Authored-By: Mac L <mjladson@pm.me>

Cargo.toml

@@ -56,7 +56,6 @@ members = [
     "consensus/int_to_bytes",
     "consensus/merkle_proof",
     "consensus/proto_array",
-    "consensus/safe_arith",
     "consensus/state_processing",
     "consensus/swap_or_not_shuffle",
     "consensus/types",
@@ -225,7 +224,7 @@ ring = "0.17"
 rpds = "0.11"
 rusqlite = { version = "0.28", features = ["bundled"] }
 rust_eth_kzg = "0.9"
-safe_arith = { path = "consensus/safe_arith" }
+safe_arith = "0.1"
 sensitive_url = { path = "common/sensitive_url" }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"