Added icon resources for dark mode.

[saikei718]

Issue

• close #1076

Overview (Required)

• Toolbar icons can now be recognized even in dark mode
  • Added icon resources for dark mode.

Links

• Design: https://www.figma.com/file/MbElhCEnjqnuodmvwabh9K/DroidKaigi-2023-App-UI?node-id=56145%3A49559

Screenshot (Optional if screenshot test is present or unrelated to UI)

FYI(light)	Before(dark)	After(dark)

[saikei718]

A simple issue, but this is my first contribution! thank you! Next time I'll try a slightly more difficult issue.

[tkhs0604]

@saikei718 We are really glad to hear that it is your first contribution ✨ Any kind of contribution is quite valuable for us. We are looking for your next contribution every time 🙌