Bedrock Converse `Content_blocks` Drops Redacted Reasoning Blocks In `Output_version="V1"`

The `reasoning_content` branch in `_convert_to_v1_from_converse` only handles `text` and `signature` fields, ignoring `redacted_content`. When a block contains only `redacted_content` (opaque encrypted reasoning), the branch produces an empty `reasoning` block or drops it entirely, rather than falling through to the `non_standard` block handler.

1. Construct an AIMessage with content containing a reasoning_content block with redacted_content bytes and model_provider 'bedrock_converse'. 2. Call `msg.content_blocks` and observe it returns `{'type': 'reasoning'}` without the original bytes. 3. In a multi-turn chat with Bedrock Converse and `output_version='v1'`, the second turn's request omits the reasoningContent block.

This change preserves redacted reasoning as non_standard blocks, but may affect serialization or deserialization in older LangChain versions that do not expect non_standard blocks with reasoning_content. Rollback is straightforward: revert to the original single condition. Ensure tests cover AIMessage and AIMessageChunk, and verify that downstream consumers of non_standard blocks handle the new shape. No concurrency or multithreading risks identified.