Document OAuth Flow Settings via config (extended off Auth Handler)

[MattB-msft]

Enabled settings used for the OAuth flow to be configured based on configuration/settings of the UserAuth Handlers
relevant settings are here: https://github.com/microsoft/Agents-for-net/blob/1be827d9b593a9b1d904c02673c11656e03c2a0e/src/libraries/Builder/Microsoft.Agents.Builder/UserAuth/TokenService/OAuthSettings.cs?plain=1#L12C1-L13C1

[tracyboehrer]

@MattB-msft Did you intend this for DotNet? Because those OAuthSettings can already be set in config. I suppose you could mean "document" though.