Fix macOS crash on editor closed and reopened On Minihost Modular, the window will not be recreated correctly after closing. It's because the host does not send the effEditClose opcode.
Fix macOS crash on editor closed and reopened
On Minihost Modular, the window will not be recreated correctly after
closing. It's because the host does not send the effEditClose opcode.

When effEditOpen is reentered, fVstUI!=nullptr would short-circuit the
initialization of the editor, and continue without an existing window.

DISTRHO/DPF,DISTRHO/DPF,DISTRHO/DPF,DISTRHO/DPF