Fix release issues (#3549)

This PR fixes to issues with the release:
1. One of the DynamoDB tests was failing due to environment variables
impacting its behavior.
2. The stalled stream protection changelog entries were added in error
via merge conflict.

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

CHANGELOG.md

@@ -5,18 +5,9 @@ April 2nd, 2024
 - :bug::warning: (client, [aws-sdk-rust#1111](https://github.com/awslabs/aws-sdk-rust/issues/1111), [smithy-rs#3513](https://github.com/smithy-lang/smithy-rs/issues/3513), @Ten0) Make `BehaviorVersion` be future-proof by disallowing it to be constructed via the `BehaviorVersion {}` syntax.
 
 **New this release:**
-- :tada: (all, [smithy-rs#3485](https://github.com/smithy-lang/smithy-rs/issues/3485)) Stalled stream protection now supports request upload streams. It is currently off by default, but will be enabled by default in a future release. To enable it now, you can do the following:
-
-    ```rust
-    let config = my_service::Config::builder()
-        .stalled_stream_protection(StalledStreamProtectionConfig::enabled().build())
-        // ...
-        .build();
-    ```
 - :tada: (all, [smithy-rs#3539](https://github.com/smithy-lang/smithy-rs/issues/3539)) Add FIPS support to our Hyper 1.0-based client. Customers can enable this mode by enabling the `crypto-aws-lc-fips` on `aws-smithy-experimental`. To construct a client using the new client, consult this [example](https://github.com/awslabs/aws-sdk-rust/blob/release-2024-03-29/sdk/s3/tests/hyper-10.rs).
 
     Please note that support for Hyper 1.0 remains experimental.
-- :bug: (all, [smithy-rs#3485](https://github.com/smithy-lang/smithy-rs/issues/3485)) Stalled stream protection on downloads will now only trigger if the upstream source is too slow. Previously, stalled stream protection could be erroneously triggered if the user was slowly consuming the stream slower than the minimum speed limit.
 - (all, [smithy-rs#3389](https://github.com/smithy-lang/smithy-rs/issues/3389)) All requests are now retryable, even if they are deserialized successfully. Previously, this was not allowed.
 - (all, [smithy-rs#3539](https://github.com/smithy-lang/smithy-rs/issues/3539)) Fix bug in Hyper 1.0 support where https URLs returned an error
 

aws/SDK_CHANGELOG.next.json

@@ -283,20 +283,6 @@
       "since-commit": "f19a9da9b8f79a7c448246475539c03e1bb58d7e",
       "age": 1
     },
-    {
-      "message": "Stalled stream protection now supports request upload streams. It is currently off by default, but will be enabled by default in a future release. To enable it now, you can do the following:\n\n```rust\nlet config = aws_config::defaults(BehaviorVersion::latest())\n    .stalled_stream_protection(StalledStreamProtectionConfig::enabled().build())\n    .load()\n    .await;\n```\n",
-      "meta": {
-        "bug": false,
-        "breaking": false,
-        "tada": true
-      },
-      "author": "jdisanti",
-      "references": [
-        "smithy-rs#3485"
-      ],
-      "since-commit": "f19a9da9b8f79a7c448246475539c03e1bb58d7e",
-      "age": 1
-    },
     {
       "message": "Users may now set service-specific configuration in the environment. For more information, see [this discussion topic](https://github.com/smithy-lang/smithy-rs/discussions/3537).",
       "meta": {
@@ -341,4 +327,4 @@
     }
   ],
   "aws-sdk-model": []
-}
+}

aws/sdk/integration-tests/dynamodb/tests/shared-config.rs

@@ -9,6 +9,7 @@ use aws_sdk_dynamodb::config::{
 };
 use aws_smithy_runtime::client::http::test_util::capture_request;
 use http::Uri;
+use std::env;
 
 /// Iterative test of loading clients from shared configuration
 #[tokio::test]
@@ -35,6 +36,10 @@ async fn shared_config_testbed() {
 async fn service_config_from_profile() {
     let _ = tracing_subscriber::fmt::try_init();
 
+    // Remove env vars that could interfere with the test
+    env::remove_var("AWS_DEFAULT_REGION");
+    env::remove_var("AWS_REGION");
+
     let config = r#"
 [profile custom]
 aws_access_key_id = test-access-key-id