Athena driver allow to pass credentialsProvider from config

[trompa]

Is your feature request related to a problem? Please describe.
Hello, we are not allowed to use static credentials as per compliance with some standards, so we cannot use accesKeyID and secretAccessKey.
Passing a token wouldnt either work, as it needs to be refreshed.
Credentials field gets override by constructor so we cannot pass a crendentialsProvider

Describe the solution you'd like
I want to be able to pass a credentialsProvider on the config and have it forwarded to the AthenaClient SDK class so it handles authentication internally.
crendentials field in the AthenClientConfig accepts both credentials or credentials Provider
But it gets override.
i'd want it to left untouched if it comes filled from caller:
so a change from

        ? { accessKeyId, secretAccessKey }
        : undefined,

to

credentials = config.credentials || (accessKeyId && secretAccessKey ? { accessKeyId, secretAccessKey } : undefined);

Would be enough to allow us to pass the provider

Describe alternatives you've considered

issue #6036 explores 2 options.
Their option 2 would be superseded by this one, as it would allow to pass the object with token from outside.

So it would be their Option 1: make the config over-writeable again
Or the option presented here.

As probably the change to make the config non over-writable was done on purpose. I'd go with the option presented here.

Additional context
Add any other context or screenshots about the feature request here.

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[trompa]

I created this PR with the proposed changes
#7429