add support for conversationStartProperties in DirectLineStreaming

[stevengum]

Do not merge - Pending Service-side changes

• Service-side changes complete
• Change ConversationStartProperties to ConversationStartParameters
• E2E test
  • Verify unit tests

Description

Allow developers to provide a custom user.id and user.name to be used with Direct Line App Service Extension when starting new conversations.

Example of new code path being invoked by Web Chat:

          window.WebChat.renderWebChat(
              {
                  directLine: await window.WebChat.createDirectLineAppServiceExtension({
                      domain: '<WindowsAppServiceUrlForBot>/.bot/v3/directline',
                      token: response.token,
                      conversationStartProperties: {
                          user: {
                              id: userID,
                              name: username
                          },
                          locale: 'en-us' 
                      }
                  }),
                  store,
                  userID,
                  username
              },
              document.getElementById('webchat')
          );

Specific Changes

• fixed test suite name for happy.replaceActivityFromId.js
• added 'should use conversationStartProperties when starting conversation' test suite with Direct Line App Service Extensions test
  • test added to happy.userIdOnStartConversation.js