[Feature] Lazy import for the "mistral" tokenizer module. (#34651)

Signed-off-by: Neil Schemenauer <nas@arctrix.com>

tests/models/multimodal/processing/test_common.py

@@ -23,7 +23,7 @@ from vllm.multimodal.cache import MultiModalProcessorOnlyCache
 from vllm.multimodal.inputs import MultiModalInputs, batched_tensors_equal
 from vllm.multimodal.processing import BaseMultiModalProcessor, InputProcessingContext
 from vllm.tokenizers import TokenizerLike, cached_tokenizer_from_config
-from vllm.tokenizers.mistral import MistralTokenizer
+from vllm.utils.mistral import is_mistral_tokenizer
 
 from ....multimodal.utils import random_audio, random_image, random_video
 from ...registry import (
@@ -183,7 +183,7 @@ def get_text_token_prompts(
 
     text_prompt: str | None
     token_prompt: list[int]
-    if isinstance(tokenizer, MistralTokenizer):
+    if is_mistral_tokenizer(tokenizer):
         # ChatCompletionRequest only supports ImageChunk natively;
         # for other modalities (e.g. audio), fall back to the model's
         # own dummy inputs builder which knows the right placeholders.