test: land the vim diary -count cases + dedup the lua one (follow-up to 2da2168)

2da2168's diary test edits landed unevenly: the lua
cmd.VimwikiMakeDiaryNote_has_count case got inserted twice, and the two vim
cases (cmd.Vimwiki{MakeDiaryNote,DiaryIndex}_accepts_count) the commit message
referenced never landed (the Edit had no-matched). Remove the lua duplicate and
add the two vim cases before the harness wrap-up. lua 284, vim 274/18/21, all
0 failed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

development/tests/test-keymaps.lua

@@ -915,15 +915,6 @@ vim.defer_fn(function()
       error('VimwikiMakeDiaryNote missing -count: ' .. vim.inspect(c))
     end
   end)
-  -- Diary-note family carries -count=0 (vimwiki's wiki selector), so
-  -- `:2VimwikiMakeDiaryNote` selects wiki #2 instead of raising E481.
-  tobj_case('cmd.VimwikiMakeDiaryNote_has_count', function()
-    local c = vim.api.nvim_buf_get_commands(0, {}).VimwikiMakeDiaryNote
-    if not c then error(':VimwikiMakeDiaryNote not defined') end
-    if c.count == nil or c.count == false then
-      error('VimwikiMakeDiaryNote missing -count: ' .. vim.inspect(c))
-    end
-  end)
   -- `:VimwikiNormalizeLink 1` (the arg is upstream's visual flag; the command
   -- is -nargs=? not -range, so no `'<,'>`) wraps the last visual selection.
   tobj_case('cmd.normalize_link_visual_wraps_selection', function()