Adds: prompt to allow empty commit messages

[Abiggj]

This change introduces #5641 a confirmation prompt when attempting to commit without a message. Instead of blocking the commit with an error, lazygit now presents a menu allowing you to proceed with an empty message (automatically adding the --allow empty-message flag) or return to the editor.

• I18n: Added CommitWithoutMessagePrompt to the translation set.
• UI: Updated HandleCommitConfirm to show a menu with explicit 'y' (confirm) and 'n' (close) bindings when the commit summary is empty.
• Git Commands: Modified commitMessageArgs to append the --allow-empty-message flag when both summary and description are empty or
  whitespace-only.
• Tests: Added unit tests to pkg/commands/git_commands/commit_test.go to verify the correct construction of git commands for empty commits
  and rewords.