Backporting #2094 to set default PowerShell to latest available#2149

TylerLeonhardt merged 3 commits intoPowerShell:legacy/1.xPowerShell/vscode-powershell:legacy/1.xfrom

SydneyhSmith:cherry-pick-#2094SydneyhSmith/vscode-powershell:cherry-pick-#2094Copy head branch name to clipboard