Improve guards to avoid potential ClassCastException.

We now guard Slice conversion against potential ClassCastException using the proper condition grouping. Previously, the conversion could happen if the query is a slice query while the source was not a Slice.

Resolves #2296.

Author: mp911de

src/main/java/org/springframework/data/repository/query/ResultProcessor.java

@@ -143,7 +143,7 @@ public <T> T processResult(@Nullable Object source, Converter<Object, Object> pr
 
 		ChainingConverter converter = ChainingConverter.of(type.getReturnedType(), preparingConverter).and(this.converter);
 
-		if (source instanceof Slice && method.isPageQuery() || method.isSliceQuery()) {
+		if (source instanceof Slice && (method.isPageQuery() || method.isSliceQuery())) {
 			return (T) ((Slice<?>) source).map(converter::convert);
 		}