Update Cosmos DB Management to 01-15 (Azure#18454)

* auto generated code from 01-15

* update tests

* change version

* changes

* update tests

* Change APIversion in props

* re-run tests

* regenerate after change to modelAsString=false and rerun tests

* Change version to 2.0

* Regenerate + rerun tests with version 2.0

* test files

* Run generate.psq

* Update comment for new version in csproj and rerun generate to try to match generated code in linter

* Remove lines from BackupPolicy manually

Author: kristynhamasaki

eng/mgmt/mgmtmetadata/cosmos-db_resource-manager.txt

@@ -3,12 +3,12 @@ AutoRest installed successfully.
 Commencing code generation
 Generating CSharp code
 Executing AutoRest command
-cmd.exe /c autorest.cmd https://github.com/Azure/azure-rest-api-specs/blob/master/specification/cosmos-db/resource-manager/readme.md --csharp --version=v2 --reflect-api-versions --tag=package-2020-06-preview --csharp-sdks-folder=D:\azure-sdk-for-net-nichatur\sdk
-2021-02-09 19:26:39 UTC
+cmd.exe /c autorest.cmd https://github.com/Azure/azure-rest-api-specs/blob/master/specification/cosmos-db/resource-manager/readme.md --csharp --version=v2 --reflect-api-versions --csharp-sdks-folder=C:\Users\kristynh\azure-sdk-for-net\sdk
+2021-02-13 01:16:50 UTC
 Azure-rest-api-specs repository information
 GitHub fork: Azure
 Branch:      master
-Commit:      0d32cdfc7fae7d13fe02800c277e2e66ad86cfa9
+Commit:      dfedab416d1c4fe521f6f3c58cdcb0da37107b84
 AutoRest information
 Requested version: v2
 Bootstrapper version:    autorest@2.0.4413

sdk/cosmosdb/Microsoft.Azure.Management.CosmosDB/AzSdk.RP.props

@@ -1,7 +1,7 @@
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <!--This file and it's contents are updated at build time moving or editing might result in build failure. Take due deligence while editing this file-->
   <PropertyGroup>
-    <AzureApiTag>CosmosDB_2020-06-01-preview</AzureApiTag>
+    <AzureApiTag>CosmosDB_2021-01-15</AzureApiTag>
     <PackageTags>$(PackageTags);$(CommonTags);$(AzureApiTag);</PackageTags>
   </PropertyGroup>
 </Project>