Put an option to choose which browser to use on Connect-PnPOnline when using -LaunchBrowser

[Jfrigo]

Currently I use 2 browsers at the same time as it is a pain when you log in a customer's Microsoft environment to change and log back to other customer's or your on environment, so right now when I use -LaunchBrowser it will use my system's default browser, it would be good if I could point which browser to use so if for that script is the customer that I usually run in my non-default browser it won't get in the way when I try to log in other environment on the default browser.