Fix SqliteVectorStoreWriterTests hang: reduce test record count and use conditional MaxTopCount

src/Libraries/Microsoft.Extensions.DataIngestion/Writers/VectorStoreWriter.cs

@@ -169,7 +169,13 @@ private async Task<IReadOnlyList<object>> GetPreExistingChunksIdsAsync(Ingestion
         }
 
         // Each Vector Store has a different max top count limit, so we use low value and loop.
-        const int MaxTopCount = 1_000;
+        // Use smaller batch size in debug to be able to test the looping logic without needing to insert a lot of records.
+        const int MaxTopCount =
+#if RELEASE
+            1_000;
+#else
+            10;
+#endif
 
         List<object> keys = [];
         int insertedCount;

test/Libraries/Microsoft.Extensions.DataIngestion.Tests/Writers/VectorStoreWriterTests.cs

@@ -134,10 +134,9 @@ public async Task IncrementalIngestion_WithManyRecords_DeletesAllPreExistingChun
 
         IngestionDocument document = new(documentId);
 
-        // Create more chunks than the MaxTopCount (1000) to test pagination
-        // We create 2500 chunks to ensure multiple batches
+        // Create enough chunks to exercise the incremental ingestion delete-all behavior in DEBUG builds
         List<IngestionChunk<string>> chunks = [];
-        for (int i = 0; i < 2500; i++)
+        for (int i = 0; i < 50; i++)
         {
             chunks.Add(new($"chunk {i}", document));
         }