Remove deprecated Auth function from C++ SDK #13762

Job	Run time
check_and_prepare	21s
build-desktop-windows-latest-x64-openssl	1h 4m 44s
build-android-ubuntu-22.04	24m 17s
build-android-windows-latest	40m 14s
build-desktop-ubuntu-22.04-x64-openssl	27m 18s
build-android-macos-14	29m 49s
build-tvos-macos-14	56m 56s
build-ios-macos-14	54m 11s
test-android-ubuntu-22.04-emulator_ftl_target-gameloop	10m 56s
test-android-macos-14-android_target-gameloop	14m 1s
test-android-windows-latest-emulator_ftl_target-gameloop	9m 1s
test-android-macos-14-emulator_ftl_target-gameloop	9m 38s
test-android-ubuntu-22.04-android_target-gameloop	9m 23s
test-android-windows-latest-android_target-gameloop	15m 47s
test-ios-macos-14-ios_target-gameloop	11m 30s
test-ios-macos-14-simulator_target-gameloop	19m 55s
test-tvos-macos-14-tvos_simulator	11m 59s
test-desktop-windows-latest-x64-openssl	9m 0s
test-desktop-ubuntu-22.04-x64-openssl	4m 6s
summarize-results	19s
attempt-retry	0s
	7h 3m 25s

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