Added Changelog and bug fixes

[v1k1]

Packages impacted by this PR

@azure/cosmos

Describe the problem that is addressed by this PR

• Added changelog entries for v4.0.0 release.
• Moved logic for addition of getClientConfig from ClientContext to DiagnosticNodeInternal, so that all such logic is at one place.
• In case of exception, the logic to add request payload to diagnostic (with appropriate diagnostic level) was missing. added that.
• Added test case for verifying scope of diagnostic level is limited to CosmosClient instance.

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?)

Yes

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

APIView has identified API level changes in this PR and created following API reviews.

azure-cosmos