[Website]: Add info on Amazon Bedrock AgentCore

[alaudazzi]

Type of issue

Missing information

What documentation page is affected

https://www.elastic.co/docs/solutions/observability/applications/llm-observability

What happened?

In the section Metrics and logs ingestion for LLM APIs (via Elastic integrations):

1. Rename the title into LLM and Agentic AI Observability
2. Add Amazon Bedrock AgentCore to the table (https://www.elastic.co/docs/reference/integrations/aws_bedrock_agentcore)
3. Rename the first column to LLM and Agentic Platform or LLM provider / Agentic provider
4. Rename "Metrics and logs ingestion for LLM APIs (via Elastic integrations)" toLLM / Agent Platform Observability
5. Rename "APM tracing for LLM models (via instrumentation)"
   LLM / Agent Application Observability with APM (distributed tracing)

Additional info

No response