Assert that sceNpFriendListDialogGetResultA returns COMMON_DIALOG_ERROR_ARG_NULL on a null result pointer prior to checking for unfinished state in the initialized state, preserving 0x5a sentinels when called with a valid buffer.
Updates docs/dev/debt/libSceNpFriendListDialog.md citing native PS5 firmware 13.42 module libSceNpFriendListDialog.sprx disassembly (offset 0xa10) and native execution data showing that null result is checked before NOT_FINISHED.
The debt entry says that the notice shown with ANYPS5_PSN_DIALOGS=show is
AnyPS5's, and that what the console displays for this call without PlayStation
Network is not measured.