Don't override "Set" in certificate config providers

[TimHess]

Description

Without this change, the certificate config providers have a compatibility issue with the ConfigurationManager in .NET 6 and .UseCloudHosting (which calls webHostBuilder.UseSetting(WebHostDefaults.ServerUrlsKey, string.Join(";", urls)); and apparently tries to set the value in at least these config providers)

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[TimHess]

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