use temporary creds from AssumeRole to be able to run a headless script with amplify init

### Is this feature request related to a new or existing Amplify category?

_No response_

### Is this related to another service?

_No response_

### Describe the feature you'd like to request

A feature request was made for an Amplify CLI user to be able to run an `amplify init` (or any headless scripts) with temporary credentials. The credentials should be acquired from AWS CLI (`aws sts`), then used to assume a role to run the Amplify headless script.

### Describe the solution you'd like

The temp Amplify CLI should be able to take values set in the environment to use in the headless script.

### Describe alternatives you've considered

I haven't

### Additional context

_No response_

### Is this something that you'd be interested in working on?

- [ ] 👋 I may be able to implement this feature request

### Would this feature include a breaking change?

- [ ] ⚠️ This feature might incur a breaking change