Add a keybinding to redraw the TUI

[acuteenvy]

This Pull Request fixes/closes #2703.

It changes the following:

• Ctrl+l now redraws the TUI.

I followed the checklist:

• I added unittests
• I ran make check without errors
  I'm getting errors from tombi:

Error: "./asyncgit/Cargo.toml" is not formatted
Error: "./Cargo.toml" is not formatted
11 files did not need formatting
2 files failed to be formatted

but I didn't touch these files.

• I tested the overall application
• I added an appropriate item to the changelog