refactor: Update AstraDbEmbeddingStoreIT.java (langchain4j#863)

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## Context
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## Change
refereceEmbedding -> referenceEmbedding

## Checklist
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- [ ] I have added unit and integration tests for my change
- [ ] All unit and integration tests in the module I have added/changed
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langchain4j-cassandra/src/test/java/dev/langchain4j/store/embedding/astradb/AstraDbEmbeddingStoreIT.java

@@ -89,8 +89,8 @@ void testAddEmbeddingAndFindRelevant() {
         String id = embeddingStore.add(embedding, textSegment);
         assertThat(id != null && !id.isEmpty()).isTrue();
 
-        Embedding refereceEmbedding = Embedding.from(new float[]{8.7F, 4.5F, 3.4F, 1.2F, 5.5F, 5.6F, 6.4F, 5.5F, 8.1F, 9.1F, 1.1F});
-        List<EmbeddingMatch<TextSegment>> embeddingMatches = embeddingStore.findRelevant(refereceEmbedding, 1);
+        Embedding referenceEmbedding = Embedding.from(new float[]{8.7F, 4.5F, 3.4F, 1.2F, 5.5F, 5.6F, 6.4F, 5.5F, 8.1F, 9.1F, 1.1F});
+        List<EmbeddingMatch<TextSegment>> embeddingMatches = embeddingStore.findRelevant(referenceEmbedding, 1);
         assertThat(embeddingMatches).hasSize(1);
 
         EmbeddingMatch<TextSegment> embeddingMatch = embeddingMatches.get(0);