Delete service-limits.md

This file was accidentally saved into the root of Azure-docs-pr.  Checked with the contributor and he said it was an accident in PR #198780

The real, in-use file is here: https://github.com/MicrosoftDocs/azure-docs-pr/blob/main/articles/applied-ai-services/form-recognizer/service-limits.md

Safe to delete this copy in the root.

Author: JasonWHowell