AgentCore CLI Supports Building Lambda for Gateway Targets but this is not exposed through CLI Flags

### Description

AgentCore CLI Supports Building Lambda for Gateway Targets but this is not exposed through CLI Flags. This means that the only way to use this is by manually editing agentcore.json. The exact schema for this is also unclear and not published in schema.json or llm-context folder.

### Steps to Reproduce

N/A

### Expected Behavior

This should be exposed as a configuration option when bringing in a Lambda for Gateway.

### Actual Behavior

No CLI flags are available to set compute type etc. The only way to leverage this option is through editing agentcore.json

### CLI Version

0.22.0

### Operating System

macOS

### Additional Context

_No response_