Make connection recording tests less senstive to semver hazards (#3786)

## Motivation and Context
A preparatory PR that relaxes test verification of the connection
recording tests.

## Description
This PR is a preparatory step for upcoming changes to the `UserAgent`,
which will introduce new header values in `x-amz-user-agent`, such as
`ua/2.0` (user agent metadata) and `m/A` (business metrics).

However, the introduction of new header values will cause the following
pain points:
- we have to update many connection recording tests to make them pass
again (i.e. the very places updated in this PR)
- check for semver hazards [fail to
pass](https://github.com/smithy-lang/smithy-rs/actions/runs/10209305234/job/28247956895).
This is much the same as we encountered in [content length enforcement
tests](https://github.com/smithy-lang/smithy-rs/issues/3523). This
creates a chicken-and-egg problem: tests need to be updated for the PRs
to pass CI, but the "released SDKs" in the `aws-sdk-rust` repository
won't implement the new `UserAgent` header values until the PRs are
merged and released.

To prevent recurring issues with headers affecting connection recording
tests (hence semver checks), this PR preemptively updates the connection
recording tests. Specifically, it adjusts them to ignore certain
headers, ensuring that updates to the `x-amz-user-agent` header do not
trigger semver hazards in subsequent PRs.

**Questions**:
- This PR modifies the connection recording tests to skip verification
of the `x-amz-user-agent` and `authorization` headers. Consequently, we
no longer test the SigV4 signature match in `aws/sdk/integration-tests`.
Although we continue to run canary tests in CI, it would be beneficial
to maintain at least one integration test for verifying the correctness
of the SigV4 signature. This helps in detecting potential bugs affecting
SigV4 signature correctness early on.
To address this, I’ve added [an
awsSdkIntegrationTest](https://github.com/smithy-lang/smithy-rs/blob/f513b924dc0e624d9810889b7177cb4eda6709d2/aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/SigV4AuthDecoratorTest.kt#L72)
that excludes the `UserAgentInterceptor` and checks the `Signature`
value in the `authorization` header. The question is, do we want to keep
this test? If future header updates cause semver hazards to fail, this
test would also be affected. We would then need to repeat the process we
are going through with this PR: update the test, release the change to
aws-sdk-rust, and only then can we make subsequent changes without
breaing semver hazards.

- I've removed the commented-out tests and their associated connection
recording files from `request_information_headers.rs` as part of
cleanup, since there were no explanatory comments. Let me know if we
want to restore these tests, and I will do so along with a comment
explaining their purpose.

## Testing
- Existing tests in CI

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