## Description
This does several things:
1. Upgrade to RusTLS 0.23 which enables FIPS support
2. Add smoke test of the clients. This revealed a bug where https URLs
were not supported.

This is technically a breaking change because I added `non_exhaustive`
to the CryptoMode enum.

<!--- Describe your changes in detail -->

## Testing
New integration tests. I expect this to fail in CI since I'll need to
update the build image to match.

## Checklist
<!--- If a checkbox below is not applicable, then please DELETE it
rather than leaving it unchecked -->
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the
smithy-rs codegen or runtime crates
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the AWS
SDK, generated SDK code, or SDK runtime crates

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