Remove deprecated Auth function from C++ SDK #13726

Job	Run time
check_and_prepare	29s
build-desktop-windows-latest-x64-openssl	1h 11m 43s
build-android-macos-14	39m 42s
build-android-ubuntu-22.04	26m 21s
build-ios-macos-14	53m 59s
build-android-windows-latest	41m 41s
build-desktop-ubuntu-22.04-x64-openssl	26m 8s
build-tvos-macos-14	31m 46s
test-tvos-macos-14-tvos_simulator	16m 17s
test-android-ubuntu-22.04-emulator_ftl_target-gameloop	9m 3s
test-android-macos-14-emulator_ftl_target-gameloop	10m 22s
test-android-windows-latest-android_target-gameloop	10m 15s
test-android-ubuntu-22.04-android_target-gameloop	9m 0s
test-android-windows-latest-emulator_ftl_target-gameloop	26m 57s
test-android-macos-14-android_target-gameloop	9m 13s
test-ios-macos-14-ios_target-gameloop	14m 50s
test-ios-macos-14-simulator_target-gameloop	17m 23s
test-desktop-windows-latest-x64-openssl	8m 37s
test-desktop-ubuntu-22.04-x64-openssl	4m 11s
summarize-results	23s
attempt-retry	0s
	7h 8m 20s

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