fix: restore singleton dims for LLM outputs (#1518)

Author: leejet

src/llm.hpp

@@ -1403,7 +1403,8 @@ namespace LLM {
                                    out_layers,
                                    return_all_hidden_states);
             };
-            return take_or_empty(GGMLRunner::compute<float>(get_graph, n_threads, true));
+            return restore_trailing_singleton_dims(GGMLRunner::compute<float>(get_graph, n_threads, true),
+                                                   input_ids.dim() + 1);
         }
 
         int64_t get_num_image_tokens(int64_t t, int64_t h, int64_t w) {