Remove webjoin=true from VS Code templates launch.json so Teams launcher is used

[therealjohn]

To make it simpler for developers to run and debug in web OR desktop clients, the Teams launcher is the best solution right now. The launch.json in our templates currently avoids this by passing webjoin=true in the launch URL and it's unclear why.

i.e.
"url": "https://teams.microsoft.com/l/app/${{local:TEAMS_APP_ID}}?installAppPackage=true&webjoin=true&${account-hint}",

We could remove this so it would be:
"url": "https://teams.microsoft.com/l/app/${{local:TEAMS_APP_ID}}?installAppPackage=true&${account-hint}",

Then when you start debugging from VS Code, the default experience is to open the desktop client but you can also choose web if you prefer.

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[MuyangAmigo]

@therealjohn webjoin=true is added so we could enforce the account-hint to work. Otherwise if devs open desktop client and signed into a different account they will see App Not Found error and have no idea why.