Removes unnecessary call to prepareScanResultLocked

There were two calls to prepare scan result within a dozen lines of one
another. This was not resulting in any bad behavior, but was unnecessary
and resulted in unneeded warnings.

Test: atest CtsAtomicInstallTestCases:AtomicInstallTest
Bug: 109941548
Change-Id: I8817a189cb9976382a8057fe8b2c7a638f3d0d64