fix: MultipleChunkRetrieverQa consumes chunks greedily (#773)

* `MultipleChunkRetrieverQa` consumes chunks greedily

* Remove unnecessary imports

src/intelligence_layer/use_cases/qa/multiple_chunk_retriever_qa.py

@@ -1,4 +1,3 @@
-from collections import defaultdict
 from typing import Generic, Optional, Sequence
 
 from pydantic import BaseModel
@@ -117,27 +116,27 @@ def _get_highlights_per_chunk(
     def _expand_search_result_chunks(
         self, search_results: Sequence[SearchResult[ID]], task_span: TaskSpan
     ) -> Sequence[EnrichedChunk[ID]]:
-        grouped_results: dict[ID, list[SearchResult[ID]]] = defaultdict(list)
-        for result in search_results:
-            grouped_results[result.id].append(result)
-
         chunks_to_insert: list[EnrichedChunk[ID]] = []
-        for id, results in grouped_results.items():
+        for result in search_results:
             input = ExpandChunksInput(
-                document_id=id, chunks_found=[r.document_chunk for r in results]
+                document_id=result.id, chunks_found=[result.document_chunk]
             )
             expand_chunks_output = self._expand_chunks.run(input, task_span)
             for chunk in expand_chunks_output.chunks:
                 if len(chunks_to_insert) >= self._insert_chunk_number:
                     break
-                chunks_to_insert.append(
-                    EnrichedChunk(
-                        document_id=id,
-                        chunk=chunk.chunk,
-                        indices=(chunk.start_index, chunk.end_index),
-                    )
+
+                enriched_chunk = EnrichedChunk(
+                    document_id=result.id,
+                    chunk=chunk.chunk,
+                    indices=(chunk.start_index, chunk.end_index),
                 )
 
+                if enriched_chunk in chunks_to_insert:
+                    continue
+
+                chunks_to_insert.append(enriched_chunk)
+
         return chunks_to_insert
 
     def do_run(