Commits pending system update titles, replacing the current titles.

This copies the titleIDs of system titles which did not have installation finalized yet(which were already downloaded), to a title-list buffer. If there’s any titles which were not completely downloaded, where TWL titles with titleID-high bit0 is set, or CTR titles with titleID-high bit5 set, NIM will then return without using any AM commands. NIM will then use AMNet:InstallTitlesFinish(mediatype=NAND) with the above title-list buffer, and then use command AMNet:FinishInstallToMedia(mediatype=NAND).