Keep XObject decodability check without binding content in interp

crates/redact/src/interp.rs

@@ -443,7 +443,7 @@ fn content_draws(doc: &Document, content: &[Vec<u8>], xo: &Dict, name: &[u8], de
         if depth >= MAX_DEPTH {
             return None;
         }
-        let Ok(data) = s.decoded() else { return None };
+        let Ok(_data) = s.decoded() else { return None };
         match content_draws(doc, content, xo, name, depth + 1, seen) {
             Some(false) => {}
             other => return other,