REPL output prefix logic broken in history mode on 1.9

[pfitzseb]

The output prefix logic in display(::REPLDisplay) assumes that the REPL is in normal mode, not in history mode.

This means that code like the following will fail

julia> @async begin
         try
           sleep(2)
           display(Base.Multimedia.displays[2], 2) # Base.Multimedia.displays[2] is the REPLDisplay for me
         catch err
           @error "cant display" ex=(err, catch_backtrace())
         end
       end
Task (runnable) @0x00007f0ed7f08fb0

julia> 1+1┌ Error: cant display
│   ex =
│    MethodError: no method matching write_output_prefix(::IOContext{Base.TTY}, ::REPL.LineEdit.PrefixHistoryPrompt, ::Bool)
│
│    Closest candidates are:
│      write_output_prefix(::IO, ::REPL.LineEdit.Prompt, ::Bool)
│       @ REPL ~/.julia/juliaup/julia-1.9.0-rc1+0.x64.linux.gnu/share/julia/stdlib/v1.9/REPL/src/LineEdit.jl:1472
│
│    Stacktrace:
│     [1] (::REPL.var"#55#56"{REPL.REPLDisplay{REPL.LineEditREPL}, MIME{Symbol("text/plain")}, Base.RefValue{Any}})(io::Any)
│       @ REPL ~/.julia/juliaup/julia-1.9.0-rc1+0.x64.linux.gnu/share/julia/stdlib/v1.9/REPL/src/REPL.jl:267
│     [2] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
│       @ REPL ~/.julia/juliaup/julia-1.9.0-rc1+0.x64.linux.gnu/share/julia/stdlib/v1.9/REPL/src/REPL.jl:555
│     [3] display(d::REPL.REPLDisplay, mime::MIME{Symbol("text/plain")}, x::Any)
│       @ REPL ~/.julia/juliaup/julia-1.9.0-rc1+0.x64.linux.gnu/share/julia/stdlib/v1.9/REPL/src/REPL.jl:262
│     [4] display
│       @ ~/.julia/juliaup/julia-1.9.0-rc1+0.x64.linux.gnu/share/julia/stdlib/v1.9/REPL/src/REPL.jl:279 [inlined]
│     [5] macro expansion
│       @ ./REPL[4]:4 [inlined]
│     [6] (::var"#5#6")()
│       @ Main ./task.jl:514
└ @ Main REPL[4]:6

when moving back in the REPL history after starting the async task. Here's an asciinema recording for illustration purposes.