Propagate command context through IAM and creator AWS operations

Summary

Propagate the command context.Context through IAM role and policy operations and through the creator lookup.

Rationale

The IAM service-account create command receives a command context. The current creator lookup and role bridge do not propagate that context to the underlying AWS operations. A cancelled command can therefore remain blocked in an AWS call.

Required changes

• Add context-accepting AWS client APIs for the creator lookup and IAM role/policy operations.
• Update pkg/aws/rolebridge to pass the supplied context to those APIs.
• Update cmd/create/iamserviceaccount/cmd.go to use the context-aware creator lookup and IAM adapter.
• Preserve cancellation and timeout behavior for EnsureRole, AttachRolePolicy, and PutRolePolicy.
• Add tests that verify context propagation and cancellation behavior.

Affected areas

• cmd/create/iamserviceaccount/cmd.go
• pkg/aws/rolebridge
• AWS client interfaces and implementations that provide creator and IAM operations

Acceptance criteria

• The command context reaches the creator lookup and all IAM role/policy AWS calls.
• Cancellation or deadline expiry stops the affected AWS operations when the AWS SDK supports it.
• Tests cover forwarding of the command context through the adapter and client APIs.

Backlinks

• Pull request: https://github.com/openshift/rosa/pull/3482
• Review comment: https://github.com/openshift/rosa/pull/3482#discussion_r3927336183
• Requested by: @markirish