Do not call retrieveMedia() if it is already done Bug: 77304533 Test: succeeded building and tested aosp Music app with 60 mp3 files. Change-Id: I69cdef1f11cf36502dffd0be41d62711adfd49d4 Merged-In: I69cdef1f11cf36502dffd0be41d62711adfd49d4 (cherry picked from commit 55e09c4068e9339986bf41890f27753b5a3ab1c2)