[DOCS] X-SM-EAR-Tag Header Param from Batch - Create new job missing in SDK

[JoeEnan]

Which documentation is affected?

• Main README.md
• RT SDK README (sdk/rt/README.md)
• Batch SDK README (sdk/batch/README.md)
• Release documentation (.github/RELEASE.md)
• Code comments/docstrings
• Examples
• Other (please specify)

Describe the issue
A clear and concise description of what's wrong with the current documentation or what's missing.

• Source: https://docs.speechmatics.com/api-ref/batch/create-a-new-job

• There is no real way to specify this tag within the speechmatics-batch SDK, unsure if the documentation is outdated, or is the SDK missing the capability to provide this header

What should be improved?
Describe what you think should be changed, added, or clarified:

• Not sure if you guys want to update the documentation as ear-tags will no longer be used by Speechmatics, or will you update the code in the SDK to include it as a optional header that we can provide to specify

Suggested content (optional)
If you have specific suggestions for how to improve the documentation, please provide them:

• Either remove X-SM-EAR-Tag Header from documentation, or update the SDK?

Impact
How does this documentation issue affect users?

• Prevents getting started with the SDK
• Makes specific features difficult to use
• Causes confusion about best practices
• Minor inconvenience
• Other (please describe)