remove unnecessary casts when calling Combobox::SetEntryData

An OUString* is type compatibile with void*.

Change-Id: I6f01fe02c75f4db0bda09c7e288cb88d1fbf3c37
remove unnecessary use of OUString*

in FileList. There no benefit in storing a ref-counted value class like
OUString by pointer in a std::vector.

Change-Id: I302bc460de67c7fe324d745f3225df4e17195486