Update enhanced-connectors with MIP contract.md

[jas-valgotar]

This pull request updates the docs/enhanced-connectors.md file to include new metadata for sensitivity labels applied to table columns. The most important change is the addition of the x-ms-content-sensitivityLabelInfo property, which provides detailed metadata about sensitivity labels, including an example JSON object for clarity.

Documentation update:

• Added a new property, x-ms-content-sensitivityLabelInfo, to describe metadata about sensitivity labels applied to table columns. The metadata includes properties such as sensitivityLabelId, name, displayName, priority, color, and others. An example JSON object illustrating the structure of this property was also included. ([docs/enhanced-connectors.mdR187-R204](diffhunk://#diff-c5943549bf367bbd0775d7fd90401982f9983ad33f2b62e89bb1fda325919d24R187-R204))

[LucGenetier]

✅ No public API change.

[jas-valgotar]

✅ No public API change.

[jas-valgotar]

✅ No public API change.

[jas-valgotar]

✅ No public API change.