fix(adapter-xhr): Only modify the responseType if it was changed

[offirgolan]

Description

Modifying the responseType for synchronous requests is not allowed. Since we really just need to override blob or arraybuffer to arraybuffer and not default it to text, I moved the logic into an if statement which should naturally add support back to synchronous requests.

Motivation and Context

Resolves #356.

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have added tests to cover my changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• My code follows the code style of this project.
• My commits and the title of this PR follow the Conventional Commits Specification.
• I have read the contributing guidelines.