[Cosmos DB] Release 4.5.0

[ealsur]

This PR prepares the 4.5.0 release which includes

1. Bumping the SDK to 3.38.1
2. Applying a temporary fix to Scale Controller Metrics APIs. When the Scale Controller runs and the customer Function instances are dormant, there is a chance that the monitored container splits. In this case, the Metrics API is throwing a CosmosException with StatusCode 410. The solution is to return a Metric value that would prompt the Scale Controller to at least start 1 instance, which will take care of handling the split.

Bumping to SDK to 3.38.1 includes related fixes to the Extension:

• 4220 Change Feed Processor: Fixes disposal of unused CancellationTokenSource (#4220)
• 4276 Change Feed Processor: Fixes LeaseLostException on Notifications API for Renewer (#4276)
• 4251 Emulator : Adds support for flag in connection string to ignore SSL check (#4251)

Along other general improvements: https://raw.githubusercontent.com/Azure/azure-cosmos-dotnet-v3/master/changelog.md

Closes #762