RootCanal: Fix length of page_number slice in SendCommandToRemoteByAddress

The code is reading two bytes for the page_number, it fails because
the page_number is only 1 byte long and the last parameter
of the Read Remote Extended Features command.

        Assertion failed: ((offset + size) <= size_), function subrange, file
        /Volumes/Android/buildbot/src/android/emu-master-dev/external/rust/crates/pdl-compiler/scripts/packet_runtime.h,
        line 45.

Bug: 296537295
Test: manual
Change-Id: I5241d666a2ebf8b167b9293163575e0022796422