Accumulate OAuth scopes across step-up authorization challenges #2569

Job	Run time
build (windows-latest, Release)	12m 7s
build (windows-latest, Debug)	12m 7s
build (macos-latest, Release)	7m 1s
build (ubuntu-latest, Debug)	12m 56s
build (macos-latest, Debug)	7m 17s
build (ubuntu-latest, Release)	6m 45s
publish-coverage	0s
	58m 13s

Provide feedback