Add emoji fallback images for V4

public/-/emojis/4/flexed_biceps_light_skin_tone.png

public/-/emojis/4/flexed_biceps_medium_dark_skin_tone.png

public/-/emojis/4/flexed_biceps_medium_light_skin_tone.png

public/-/emojis/4/flexed_biceps_medium_skin_tone.png

public/-/emojis/4/floppy_disk.png

public/-/emojis/4/flower_playing_cards.png

public/-/emojis/4/flushed_face.png

public/-/emojis/4/flute.png

public/-/emojis/4/fly.png

public/-/emojis/4/flying_disc.png

public/-/emojis/4/flying_saucer.png

public/-/emojis/4/fog.png

public/-/emojis/4/foggy.png

public/-/emojis/4/folded_hands.png

public/-/emojis/4/folded_hands_dark_skin_tone.png

public/-/emojis/4/folded_hands_light_skin_tone.png

public/-/emojis/4/folded_hands_medium_dark_skin_tone.png

public/-/emojis/4/folded_hands_medium_light_skin_tone.png

public/-/emojis/4/folded_hands_medium_skin_tone.png

public/-/emojis/4/folding_hand_fan.png