Cosmos DB: Added regions_contacted as new dimension and operation count metrics

[sourabh1007]

Dimensions

Tag/dimension name	Sample value	Description
db.cosmosdb.regions_contacted	"North Central US,Central US", "East US 2,North Central US"	It would help us to identify if operation call was cross regional or single regional calls

Metrics

Name	Unit	Type	Description
db.cosmosdb.operation.count	{operations}	counter	Total number of executed operations. This metric will help assess the success and failure rates of operations and identify patterns in case of failures.

ref. #1438
and https://github.com/Azure/azure-sdk-for-java/blob/main/sdk/cosmos/azure-cosmos/docs/Metrics.md

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• schema-next.yaml updated with changes to existing conventions.