fix(rust): handle disk cache topology

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm-rust/crates/python-bridge/src/cache/native.rs

@@ -83,6 +83,7 @@ impl NativeResponseCache {
         match self {
             Self::Memory(_) => None,
             Self::Redis { cache, .. } => Some(cache.backend().topology()),
+            Self::Disk(_) => None,
         }
     }