Remove CohereReRank and LlmLongLingua breaking imports (#11023)

llama-index-core/llama_index/core/indices/postprocessor.py

 # for backward compatibility
 from llama_index.core.postprocessor import (
     AutoPrevNextNodePostprocessor,
-    CohereRerank,
     EmbeddingRecencyPostprocessor,
     FixedRecencyPostprocessor,
     KeywordNodePostprocessor,
     LLMRerank,
     LongContextReorder,
-    LongLLMLinguaPostprocessor,
     MetadataReplacementPostProcessor,
     NERPIINodePostprocessor,
     PIINodePostprocessor,
@@ -31,13 +29,11 @@ __all__ = [
     "TimeWeightedPostprocessor",
     "PIINodePostprocessor",
     "NERPIINodePostprocessor",
-    "CohereRerank",
     "LLMRerank",
     "SentenceEmbeddingOptimizer",
     "SentenceTransformerRerank",
     "MetadataReplacementPostProcessor",
     "LongContextReorder",
-    "LongLLMLinguaPostprocessor",
     "FlagEmbeddingReranker",
     "RankGPTRerank",
     "BaseNodePostprocessor",