UserspaceEmulator: Profiles are now expected to have a strings array

The kernel profiles were recently changed to have a `strings` array
as part of the profile objects. The `ProfileViewer` now checks for
that during startup and declares the profile invalid if the array
is not present.

The UserspaceEmulator doesn't use the API which the kernel exposed
the string array for, so just fake it by always adding an empty array
to the generated profiles.

Userland/DevTools/UserspaceEmulator/main.cpp

@@ -110,7 +110,7 @@ int main(int argc, char** argv, char** env)
     rc = emulator.exec();
 
     if (dump_profile)
-        emulator.profile_stream().write_or_error(R"(]})"sv.bytes());
+        emulator.profile_stream().write_or_error(R"(], "strings": []})"sv.bytes());
 
     return rc;
 }