[9.x] Add method to AwsS3V3Adapter

[dododedodonl]

Make it convenient to retrieve the client of \Illuminate\Filesystem\AwsS3V3Adapter, like getDriver() or getAdapter() of \Illuminate\Filesystem\FilesystemAdapter

[keironlowe-edriving]

Could someone clarify how we use this? When I use Storage::disk('s3')->getAdapter() it returns an instance of League\Flysystem\AwsS3V3\AwsS3V3Adapter, not Illuminate\Filesystem\AwsS3V3Adapter.
Thanks

[dododedodonl]

Storage::disk('s3') already returns Illuminate\Filesystem\AwsS3V3Adapter, ->getAdapter() returns the underlying flysystem adapter.

[keironlowe-edriving]

@dododedodonl Thank you!