Use dialogHelper.runDialog in javascript samples containing dialogs

[EricDahlvang]

Javascript samples and this document ( https://docs.microsoft.com/en-us/azure/bot-service/bot-builder-dialog-manage-conversation-flow?view=azure-bot-service-4.0&tabs=javascript#create-the-main-dialog ) currently demonstrate creating a run method when using dialogs. The sdk has a dialogHelper.runDialog method with this same code (as well as code specific to skills).

Describe the solution you'd like Use dialogHelper.runDialog in samples, rather than a custom implementation in each sample.