Add flag FLAG_ACTIVITY_CLEAR_TOP to reopen existing Activity

In case ESOS questionnaire is invoked several times without exit, only a single instance of questionnaire is shown at one time.

Bug: 349145955
Flag: EXEMPT bugfix
Test: manual e2e test using shieldbox for both T911 and ESOS
Change-Id: I4662939fa98b66fec77ff257ff33128580e1959e
Merged-In: I4662939fa98b66fec77ff257ff33128580e1959e