Binary safe session (using SDK fix)

[dnsl48]

Using binary safe data type for session storage

This should land into 4.1, since it's explicitly increasing minimal required AWS SDK version up to ~3.105

[dhensby]

We can't be removing classes in minor version bumps, it can only be done for major bumps.

[dnsl48]

Fair enough. However, these classes were added in a patch release as a hotfix and marked as @internal. That isn't public API.
This patch is supposed to merely remove the hotfix after the bug was fixed upstream.

[dhensby]

OK - if they were added in a patch release, they can be removed in a patch release