fix(cli): do not print credentials refreshed by plugins (#33398)

### Issue #33394

Closes #33394

### Reason for this change

In #32354 we started logging credentials provided by a plugin to `stderr`. In #32708 we changed the log statement in a way that the credentials would be logged to `stdout` in CI environments (but still to `stderr` in all other environments).

### Description of changes

Do not log credentials.

### Describe any new or updated permissions being added

n/a

### Description of how you validated changes

n/a

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: mrgrain

packages/aws-cdk/lib/api/aws-auth/credential-plugins.ts

@@ -1,8 +1,8 @@
-import { inspect, format } from 'util';
+import { inspect } from 'util';
 import type { CredentialProviderSource, ForReading, ForWriting, PluginProviderResult, SDKv2CompatibleCredentials, SDKv3CompatibleCredentialProvider, SDKv3CompatibleCredentials } from '@aws-cdk/cli-plugin-contract';
 import type { AwsCredentialIdentity, AwsCredentialIdentityProvider } from '@smithy/types';
 import { credentialsAboutToExpire, makeCachingProvider } from './provider-caching';
-import { debug, warning, info } from '../../logging';
+import { debug, warning } from '../../logging';
 import { AuthenticationError } from '../../toolkit/error';
 import { formatErrorMessage } from '../../util/error';
 import { Mode } from '../plugin/mode';
@@ -151,7 +151,6 @@ function v3ProviderFromV2Credentials(x: SDKv2CompatibleCredentials): AwsCredenti
 
 function refreshFromPluginProvider(current: AwsCredentialIdentity, producer: () => Promise<PluginProviderResult>): AwsCredentialIdentityProvider {
   return async () => {
-    info(format(current), Date.now());
     if (credentialsAboutToExpire(current)) {
       const newCreds = await producer();
       if (!isV3Credentials(newCreds)) {