Move new resources into flagged subdirectory

r.android.com/1909373 added several new resources and strings.  All of
the code that referred to them was flag-guarded, but the resources
themselves weren't.  Since these aren't needed at all when the flag is
diabled, move all the new resources into a flag-guarded subdirectory.

Bug: 374764554
Test: m BuiltInPrintService
Flag: com.android.bips.flags.printer_info_details
Change-Id: I1879b59ab4d8a78b77a3b1d287d6660f26c452b6