fix web issues

[LucasXu0]

• unable to input text on Web platform
• focus will lost when typing slash
• command shortcuts on the web platform should also respect the operating system

[codecov]

Codecov Report

Patch coverage: 64.70% and project coverage change: +0.11% 🎉

Comparison is base (8e61846) 80.48% compared to head (04379e9) 80.59%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #498      +/-   ##
==========================================
+ Coverage   80.48%   80.59%   +0.11%     
==========================================
  Files         281      280       -1     
  Lines       11800    11768      -32     
==========================================
- Hits         9497     9485      -12     
+ Misses       2303     2283      -20     

Files Changed	Coverage Δ
...tor_component/service/keyboard_service_widget.dart	87.60% <ø> (ø)
...component/service/ime/non_delta_input_service.dart	83.20% <50.00%> (ø)
lib/src/editor/util/platform_extension.dart	77.27% <58.33%> (-22.73%)	⬇️
...nent/service/shortcuts/command_shortcut_event.dart	69.23% <100.00%> (+3.37%)	⬆️

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