Upgrade Smithy to 1.49 (#3662)

## Motivation and Context
Upgrades Smithy to 1.49.0

## Description
As part of the upgrade, it updates the serializer for EC2 query protocol
to handle empty lists in response to
[this](https://github.com/smithy-lang/smithy/pull/2269) (otherwise [a
protocol
test](https://github.com/smithy-lang/smithy-rs/blob/main/codegen-client-test/build.gradle.kts#L75)
`ec2_empty_query_lists_request` would fail).

## Testing
Existing tests in CI

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