feat: improve command handling for _typer and _clipper

[chkg2a]

BEMOJI_CLIP_CMD="wl-copy" # which clipboard tool to use
BEMOJI_TYPE_CMD="wtype" # which typing tool to use (ydotool will NOT work)

These two environment variables were misleading. As inside the code. It was looking for the whole command. Otherwise it was failing. The change below was made.

BEMOJI_CLIP_CMD="xclip -selection clipboard" # you need to supply the full command otherwise it won't work
BEMOJI_TYPE_CMD="xdotool type --delay 30" # which typing tool to use, input the full command

[chkg2a]

Modified _typer and _clipper to better handle the BEMOJI_TYPE_CMD and BEMOJI_CLIP_CMD variables.

• If the variable contains multiple words, it is executed as a full command using ${VAR[@]}.
• If it contains a single-word command (wtype, xdotool, wl-copy, xclip, or xsel), the script checks its availability before execution.
• Preserves the fallback mechanism for Wayland/X11 clipboard and typing tools.
• Ensures better compatibility and avoids unnecessary execution of undefined or unavailable commands.