Avoiding client-side parsing errors when Gateway returns duplicate unqiueKeyPolicy in IndexPolicy (invalid json)

[FabianMeiswinkel]

Description

Defense in depth - since Gateway in two incidents has returned index policy with duplicated uniqueKeyPolicy property we will always allow duplicates for container metadata

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[azure-sdk]

API change check

API changes are not detected in this pull request.

[kushagraThapar]

LGTM, is there any way we can add tests for this.

[jeet1995]

Can we add a unit test covering the deserialize flow when uniqueKeyPolicy or whatever property for DocumentCollection is repeated > 1 time? Also, the CHANGELOG update.

[jeet1995]

LGTM - thanks!