CopilotChat: add missing container (microsoft#1533)

### Motivation and Context
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This fixes an
[issue](microsoft#1402) with
uploading documents from the copilot chat sample app when Azure Cosmos
DB resources are used.

### Description
The `chatmemorysources` Cosmos DB container referenced in the web API
appsettings.json was missing from the bicep template and this caused the
"resource not found" error.


### Contribution Checklist
<!-- Before submitting this PR, please make sure: -->
- [x] The code builds clean without any errors or warnings
- [x] The PR follows SK Contribution Guidelines
(https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
- [x] The code follows the .NET coding conventions
(https://learn.microsoft.com/dotnet/csharp/fundamentals/coding-style/coding-conventions)
verified with `dotnet format`
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

Co-authored-by: Craig Presti <146438+craigomatic@users.noreply.github.com>
Co-authored-by: Adrian Bonar <56417140+adrianwyatt@users.noreply.github.com>

samples/apps/copilot-chat-app/deploy/main.bicep

@@ -204,6 +204,10 @@ resource appServiceWebConfig 'Microsoft.Web/sites/config@2022-09-01' = {
         name: 'ChatStore:Cosmos:ChatMessagesContainer'
         value: 'chatmessages'
       }
+      {
+        name: 'ChatStore:Cosmos:ChatMemorySourcesContainer'
+        value: 'chatmemorysources'
+      }
       {
         name: 'ChatStore:Cosmos:ConnectionString'
         value: deployCosmosDB ? cosmosAccount.listConnectionStrings().connectionStrings[0].connectionString : ''
@@ -632,6 +636,37 @@ resource participantContainer 'Microsoft.DocumentDB/databaseAccounts/sqlDatabase
   }
 }
 
+resource memorySourcesContainer 'Microsoft.DocumentDB/databaseAccounts/sqlDatabases/containers@2023-04-15' = if (deployCosmosDB) {
+  parent: cosmosDatabase
+  name: 'chatmemorysources'
+  properties: {
+    resource: {
+      id: 'chatmemorysources'
+      indexingPolicy: {
+        indexingMode: 'consistent'
+        automatic: true
+        includedPaths: [
+          {
+            path: '/*'
+          }
+        ]
+        excludedPaths: [
+          {
+            path: '/"_etag"/?'
+          }
+        ]
+      }
+      partitionKey: {
+        paths: [
+          '/id'
+        ]
+        kind: 'Hash'
+        version: 2
+      }
+    }
+  }
+}
+
 resource speechAccount 'Microsoft.CognitiveServices/accounts@2022-12-01' = if (deploySpeechServices) {
   name: 'cog-${uniqueName}'
   location: location