[Feature Request] Amplify CLI support AWS SSO

**Describe the bug**
```
$ amplify env pull
⠦ Fetching updates to backend environment: dev from the cloud.(node:10308) UnhandledPromiseRejectionWarning: Error: connect EHOSTUNREACH 169.254.169.254:80
at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1141:16)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:10308) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:10308) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
⠋ Fetching updates to backend environment: dev from the cloud.
```
**Amplify CLI Version**
4.21.1

**To Reproduce**

1. aws sso login --profile dev
2. amplify pull or amplify env pull

**Expected behavior**
Update my local development environment

**Desktop**
- OS: Linux Mint 19.3
- Node Version. v14.3.0

Start by reproducing the reported flow with `aws sso login --profile dev`, then run `amplify pull` or `amplify env pull` and inspect how the CLI handles AWS credentials. Done means both commands update the local development environment without attempting the unreachable metadata endpoint when an AWS SSO profile is active.

Written by the indexing model from the issue text.