feat(bedrock/vertex): add parity for beta messages (stream, count_tokens, parse, tool_runner)

[Ashutosh0x]

feat(bedrock/vertex): add parity for beta messages (stream, count_tokens, parse, tool_runner)

This PR adds missing beta method delegations to the AnthropicBedrock and AnthropicVertex clients, resolving #1120.

Changes

• Added stream(), count_tokens(), parse(), and tool_runner() to AnthropicBedrock.beta.messages (sync and async).
• Added parse() and tool_runner()toAnthropicVertex.beta.messages` (sync and async).
• Added corresponding method delegations to WithRawResponse and WithStreamingResponse wrappers for both cloud clients.

Verification

Verified with a reproduction script that checks for the existence and proper delegation of these methods across all cloud client variants (Bedrock/Vertex, Sync/Async).

# Now possible with Bedrock/Vertex:
with client.beta.messages.stream(...) as stream:
    for event in stream:
        ...