Refresh local model after provider setup

[SIGMAREAL]

Summary

• refresh local provider settings after the provider setup sheet completes
• keeps the Providers tab model/engine/endpoint summary in sync with reconfigured local defaults
• add a view model regression test for local model reconfiguration

Tests

• xcodebuild test -project Dayflow/Dayflow.xcodeproj -scheme Dayflow -only-testing:DayflowTests/ProvidersSettingsViewModelTests -destination 'platform=macOS' CODE_SIGNING_ALLOWED=NO\n- xcodebuild test -project Dayflow/Dayflow.xcodeproj -scheme Dayflow -only-testing:DayflowTests -destination 'platform=macOS' CODE_SIGNING_ALLOWED=NO\n\nFixes It shows old model after re-configuring a new model #245