Port counsel-kmacro to OClosures

[basil-conto]

Also fix action functions to support being ivy-called without exiting the completion session.

• counsel-kmacro-kill: Try to prevent being called outside of counsel-kmacro minibuffer completion.
• counsel-kmacro: Fix docstring. Ensure kmacro.el is loaded before evaluating any variables it defines. Remove kmacro-counter from prompt; it is already listed per-kmacro in ring. Do not default to kmacro-initial-counter-value; defer to kmacro-specific counter. Reword docs and action labels to avoid confusion between kmacro-initial-counter-value and kmacro-counter.
• counsel--kmacro-format-function: Simplify.
• counsel--with-kmacro: New macro for destructuring a kmacro object.
• counsel--format-kmacro: New function.
• counsel--kmacro-candidates: Use it and counsel--with-kmacro to format kmacro ring objects. Use kmacro-ring-head. Fix stale edmacro-fix-menu-commands warning message. Clarify docstring.
• counsel--kmacro-exec: New compatibility shim for kmacro-exec-ring-item.
• counsel-kmacro-action-run: Improve docstring. Fix current-prefix-arg usage and let ivy-current-prefix-arg override it. Use counsel--kmacro-exec. Update ivy-last for non-exiting ivy-call.
• counsel-kmacro-action-delete-kmacro: Check whether candidate is in kmacro-ring before deleting, instead of comparing to last-kbd-macro. Use kmacro-delete-ring-head. Update ivy-last state for ivy-call.
• counsel-kmacro-action-copy-initial-counter-value, counsel-kmacro-action-copy-counter-format-for-new-macro: Use counsel--with-kmacro for slot access. Clarify docstrings.
• counsel--kmacro-cycle-until: New function.
• counsel-kmacro-action-cycle-ring-to-macro: Use it for bounded ring cycling. Update ivy-last for non-exiting ivy-call.
• counsel-kmacro-action-set-saved-starting-counter: Clarify docstring. Avoid having to construct a kmacro object directly by cycling ring, reading new counter, and cycling back. Use read-number. Update ivy-last state for ivy-call.
• counsel-kmacro-action-execute-after-prompt: Improve docstring. Fix current-prefix-arg usage and let ivy-current-prefix-arg override it. Use read-number, read-string, and format-prompt. Avoid kmacro destructuring via counsel--kmacro-exec.

Fixes: #3066
Cc: @okamsn