Remove deprecated APIs (#81)

## Change
This is part of langchain4j/langchain4j#2726

Removed:
- `BertTokenizer` -> Replaced by: `HuggingFaceTokenizer`
- `OnnxEmbeddingModel(Path)` -> Replaced by: `OnnxEmbeddingModel(Path,
Path, PoolingMode)`
- `OnnxEmbeddingModel(String)` -> Replaced by: `OnnxEmbeddingModel(Path,
Path, PoolingMode)`

## General checklist
- [ ] There are no breaking changes
- [ ] I have added unit and/or integration tests for my change
- [ ] The tests cover both positive and negative cases
- [x] I have manually run all the unit and integration tests in the
module I have added/changed, and they are all green
- [ ] I have added/updated the
[documentation](https://github.com/langchain4j/langchain4j/tree/main/docs/docs)
- [ ] I have added an example in the [examples
repo](https://github.com/langchain4j/langchain4j-examples) (only for
"big" features)
- [ ] I have added/updated [Spring Boot
starter(s)](https://github.com/langchain4j/langchain4j-spring) (if
applicable)

Author: dliubarskyi

langchain4j-embeddings/src/main/java/dev/langchain4j/model/embedding/onnx/BertTokenizer.java

@@ -1,7 +1,7 @@
 package dev.langchain4j.model.embedding.onnx;
 
 import ai.djl.huggingface.tokenizers.Encoding;
-import dev.langchain4j.data.message.ChatMessage;
+import dev.langchain4j.data.message.*;
 import dev.langchain4j.model.Tokenizer;
 
 import java.io.InputStream;
@@ -101,7 +101,17 @@ public int estimateTokenCountInText(String text) {
 
     @Override
     public int estimateTokenCountInMessage(ChatMessage message) {
-        return estimateTokenCountInText(message.text());
+        if (message instanceof SystemMessage systemMessage) {
+            return estimateTokenCountInText(systemMessage.text());
+        } else if (message instanceof UserMessage userMessage) {
+            return estimateTokenCountInText(userMessage.singleText());
+        } else if (message instanceof AiMessage aiMessage) {
+            return estimateTokenCountInText(aiMessage.text());
+        } else if (message instanceof ToolExecutionResultMessage toolExecutionResultMessage) {
+            return estimateTokenCountInText(toolExecutionResultMessage.text());
+        } else {
+            throw new IllegalArgumentException("Unknown message type: " + message);
+        }
     }
 
     @Override

langchain4j-embeddings/src/main/java/dev/langchain4j/model/embedding/onnx/HuggingFaceTokenizer.java

@@ -70,31 +70,6 @@ public OnnxEmbeddingModel(String pathToModel, String pathToTokenizer, PoolingMod
         this(Paths.get(pathToModel), Paths.get(pathToTokenizer), poolingMode, executor);
     }
 
-    /**
-     * @param pathToModel The path to the modelPath file (e.g., "/path/to/model.onnx")
-     * @deprecated Use {@link OnnxEmbeddingModel#OnnxEmbeddingModel(Path, Path, PoolingMode)} or
-     * {@link OnnxEmbeddingModel#OnnxEmbeddingModel(String, String, PoolingMode)} instead.
-     */
-    @Deprecated(forRemoval = true)
-    public OnnxEmbeddingModel(Path pathToModel) {
-        super(null);
-        this.onnxBertBiEncoder = loadFromFileSystem(
-                pathToModel,
-                OnnxEmbeddingModel.class.getResourceAsStream("/bert-tokenizer.json"),
-                PoolingMode.MEAN
-        );
-    }
-
-    /**
-     * @param pathToModel The path to the modelPath file (e.g., "/path/to/model.onnx")
-     * @deprecated Use {@link OnnxEmbeddingModel#OnnxEmbeddingModel(Path, Path, PoolingMode)} or
-     * {@link OnnxEmbeddingModel#OnnxEmbeddingModel(String, String, PoolingMode)} instead.
-     */
-    @Deprecated(forRemoval = true)
-    public OnnxEmbeddingModel(String pathToModel) {
-        this(Paths.get(pathToModel));
-    }
-
     @Override
     protected OnnxBertBiEncoder model() {
         return onnxBertBiEncoder;