Evaluate the impact of Chromium Edge on SignalR browser-based testing.

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Our browser-based tests use Karma's edge launcher, and Sauce Labs when running in the cloud. I expect that is launching Edge Legacy, rather than the Chromium-based Edge, but we should check that and look at splitting our testing so we're testing both Edge Legacy and Edge Chromium.

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Also, we can probably run Edge tests on AzDO now since Chromium Edge probably supports headless!

We're ok with shifting Edge Legacy testing to Sauce Labs.

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Pre-planning notes: Punty punt. We have Chromium coverage already.