DO NOT MERGE - fix AFM.getComponentNameFromContext()

This method broke on O-MR1 when I3abf999eb6056c1df7982780bae43b58337c0668
was chery-picked from master.

Test: cts-tradefed run commandAndExit cts-dev -m CtsAutoFillServiceTestCases \
      -t android.autofillservice.cts.AttachedContextActivityTest#testAutofill
Test: cts-tradefed run commandAndExit cts-dev -m CtsAutoFillServiceTestCases

Also individually ran tests that failed (due to flakiness) when ran in a suite:

Test: cts-tradefed run commandAndExit cts-dev -m CtsAutoFillServiceTestCases \
-t android.autofillservice.cts.OptionalSaveActivityTest#testDontShowSaveUiWhenUserManuallyFilled_oneDatasetAllRequiredFields

Test: cts-tradefed run commandAndExit cts-dev -m CtsAutoFillServiceTestCases -t android.autofillservice.cts.PreSimpleSaveActivityTest #testTapLink_tapBack_thenStartOverBySayingYesAndManualRequest

Fixes: 71960322

Change-Id: Ia093dcefe6699dc9493c46d671e48c2000214b31
Merged-In: I3abf999eb6056c1df7982780bae43b58337c0668