Transcription test cleanup and Test Proxy bug work around

[alzimmermsft]

Description

Cleans up the test code in Transcription and adds in a request timeout increase to work around a performance issue in Test Proxy that causes CI to fail intermittently due to resource contention and responses from Test Proxy taking longer than 60 seconds.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[Copilot]

Pull request overview

This PR refactors the test code in the Azure AI Speech Transcription SDK to improve maintainability and adds timeout configuration to work around a Test Proxy performance issue that causes intermittent CI failures. The refactoring consolidates duplicated test logic, simplifies test methods, and uses static resource loading for better test performance.

Key changes:

• Refactored test base class to use helper methods and static audio file loading
• Simplified test methods by removing boilerplate code
• Added Maven Surefire plugin configuration with increased timeout values (300 seconds) to work around Test Proxy performance issues

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
TranscriptionClientTestBase.java	Refactored to use static audio file loading, removed test lifecycle methods, added helper methods (fromAudioFile, createMultipartBody), simplified client configuration
TranscriptionClientTest.java	Simplified all test methods to use new helper methods, added BeforeEach setup, removed repetitive client creation and method name extraction code
TranscriptionAsyncClientTest.java	Similar simplification as sync tests, proper use of StepVerifier for async validation, consolidated error handling tests
pom.xml	Added maven-surefire-plugin configuration with extended timeout values (AZURE_REQUEST_WRITE_TIMEOUT, AZURE_REQUEST_RESPONSE_TIMEOUT, AZURE_REQUEST_READ_TIMEOUT set to 300000ms)
assets.json	Formatting change from single-line to multi-line JSON

[alzimmermsft]

/check-enforcer evaluate

[alzimmermsft]

/check-enforcer override