FORMULAS feature is unconditionally set in Azure Document Intelligence converter

Problem

When using Azure Document Intelligence via markitdown,
DocumentAnalysisFeature.FORMULAS is always enabled, even when formula recognition is not required.

This behavior leads to degraded recognition accuracy, especially for documents that do not contain mathematical formulas.

The relevant code is here:
https://github.com/microsoft/markitdown/blob/main/packages/markitdown/src/markitdown/converters/_doc_intel_converter.py#L232

# _doc_intel_converter.py
features=[
    DocumentAnalysisFeature.FORMULAS,
    DocumentAnalysisFeature.TABLES,
]

Currently, FORMULAS is unconditionally included in the features list, making it impossible to disable.

Steps to Reproduce

1. Configure Azure Document Intelligence and enable it in markitdown
2. Analyze a document that does not contain mathematical formulas
3. Observe the extracted text / structure quality
4. Compare results with and without the FORMULAS feature enabled

Expected Behavior

• DocumentAnalysisFeature.FORMULAS should be optional and only enabled when explicitly requested
  or

• It should be disabled by default for general-purpose document parsing

Start in packages/markitdown/src/markitdown/converters/_doc_intel_converter.py around the features list at line 232. Trace how Azure Document Intelligence options are configured and determine how formula recognition should be made optional or disabled by default. Done means FORMULAS is not unconditionally enabled and general-purpose conversion preserves the expected extraction quality.