Fix S3Express utils and tests for auth scheme resolution pipeline migration

[S-Saranya1]

Motivation and Context

After moving auth scheme resolution and endpoint resolution from interceptors to pipeline stages (#6755, #6820), S3ExpressUtils methods that checked RESOLVED_ENDPOINT or SELECTED_AUTH_SCHEME no longer work at interceptor time, these values aren't set until the pipeline stages run (after all interceptors).

Modifications

• S3ExpressUtils — replaced checks that depended on RESOLVED_ENDPOINT and SELECTED_AUTH_SCHEME with bucket name suffix check (--x-s3) and auth scheme options check, which work before pipeline stages run.
• EnableTrailingChecksumInterceptor and DefaultS3CrtAsyncClient — updated to use the new S3ExpressUtils methods.
• EndpointResolverUtilsSpec (codegen) — pass resolved endpoint directly to business metric method instead of reading from execution attributes.
• Test interceptors — added null guard for host parsing and moved SELECTED_AUTH_SCHEME read to beforeTransmission where it's available.

Testing

Ran existing S3Express tests.

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed
• I have added a changelog entry. Adding a new entry must be accomplished by running the scripts/new-change script and following the instructions. Commit the new file created by the script in .changes/next-release with your changes.
• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license