Fix font update failure

Bug: 331717791
Test: atest UpdatableFontDirTest
Test: Step 1: Build AOSP image and install
Test: Step 2: Install font family.
Test: Step 3: Remove certificate manually by adb shell.
Test: Step 4: Reboot the device
Test: Step 5: Install font family.
Change-Id: I0373a2e66b7a6a51168094772afb36d8905b6979
Merged-In: I0373a2e66b7a6a51168094772afb36d8905b6979