Removing Unwanted Span Bar

[Ernie Braganza]

I want to have a RhythmicStaff and I see an unwanted span bar. Here's
the smallest code sample I could think of as an example. I tried  \remove
"Span_bar_engraver" but that didn't work. I've also attached a screenshot.

I am running Lilypond 2.22.1 on Debian Linux.

Thanks for your help!

\version "2.22.1"
strum =  {
  c4 c4 c4 c4  |
}
chord = \chordmode {
  c1
}
melody = {
  \time 4/4
    R1|
}
  \score {
    <<
      \new RhythmicStaff {
        \override NoteHead.style = #'slash
        \override NoteHead.font-size = #-4 \strum
      }
      \new ChordNames \chord
      \new Staff \melody
    >>
    \layout{
      \context {
        \StaffGroup
        \remove "Span_bar_engraver"  %I thought this would work
      }
      \context {
        \RhythmicStaff
        \remove "Time_signature_engraver"
        \remove "Clef_engraver"
        \override BarLine.transparent = ##t
        \override StaffSymbol.line-count = #0
      }
    }
  }