fix: unable to access the slash menu on web platform

[LucasXu0]

closes #299

[codecov]

Codecov Report

Merging #303 (e5e7fa9) into main (35394cd) will decrease coverage by 0.04%.
The diff coverage is 37.50%.

@@            Coverage Diff             @@
##             main     #303      +/-   ##
==========================================
- Coverage   70.40%   70.36%   -0.04%     
==========================================
  Files         239      239              
  Lines        9946     9951       +5     
==========================================
  Hits         7002     7002              
- Misses       2944     2949       +5     

Impacted Files	Coverage Δ
...uts/command_shortcut_events/undo_redo_command.dart	83.33% <ø> (ø)
...tcuts/character_shortcut_events/slash_command.dart	62.50% <28.57%> (-16.45%)	⬇️
...tor_component/service/keyboard_service_widget.dart	89.56% <100.00%> (ø)