Switch back to using `FilterType.Simple` for `@` filters to fix the
restore picker again.
In LocalDatabase.cs, replace code that was explicitly looking for the
presence of wildcard characters to instead trigger off of
`FilterType.Wildcard`. This fixes the "find" command.
Change FilterEntry.ToString() to prefix Simple filters with `@` so
that if simple filters with wildcard characters make the round-trip
through a string, their `FilterType.Simple` type is preserved.
Dean Ferreyra
5f972c2437