Added support for Index Metrics V2

[ujjwalsoni1707]

Packages impacted by this PR

@azure/cosmos

Issues associated with this PR

#32064

Describe the problem that is addressed by this PR

The backend currently returns Index Metrics in string format when populateIndexMetrics is sent true in query options. The backend has now introduced a V2 version of index metrics that returns the response in JSON format. This PR implements the changes for SDK to handle the new JSON format seamlessly. This change ensures compatibility with the updated backend while maintaining functionality with the previous version.

What are the possible designs available to address the problem? If there are more than one possible design, why was the one in this PR chosen?

Are there test cases added in this PR? (If not, why?)

Provide a list of related PRs (if any)

Command used to generate this PR:**(Applicable only to SDK release request PRs)

Checklists

• Added impacted package name to the issue description
• Does this PR needs any fixes in the SDK Generator?** (If so, create an Issue in the Autorest/typescript repository and link it here)
• Added a changelog (if necessary)

[azure-sdk]

API change check

API changes are not detected in this pull request.