### Godot version

4.1

### System information

Windows

### Issue description

Being able to have multiple cursors similarly to vscode is a great feature, however it's only possible to add carets, not remove them. By left clicking you can remove all extra cursors but you cannot remove a specific one so after selecting multiple lines a single missclick, you have to reselect them all again. Looking at the original pr there was a remove_caret function added so it would make sense to be able to remove carets when clicking again, like in vscode.

![image](https://github.com/godotengine/godot/assets/19669673/3867c00e-9faa-4429-9c6d-f2d6d3883044)


### Steps to reproduce

- Alt click to add multiple carets
- Alt click on the same position again
- Nothing happens

### Minimal reproduction project

N/A
if (!has_selection(caret_idx)) {
		select(line, beg, line, end, caret_idx);
		carets.write[caret_idx].selection.selecting_column = beg;
		carets.write[caret_idx].selection.selected_word_beg = beg;
		carets.write[caret_idx].selection.selected_word_end = end;
		carets.write[caret_idx].selection.selected_word_origin = beg;
		set_caret_line(line, false, true, 0, caret_idx);
		set_caret_column(end, true, caret_idx);
	} else {
		if ((col <= carets[caret_idx].selection.selected_word_origin && line == get_selection_line(caret_idx)) || line < get_selection_line(caret_idx)) {
			carets.write[caret_idx].selection.selecting_column = carets[caret_idx].selection.selected_word_end;
			select(line, beg, get_selection_line(caret_idx), carets[caret_idx].selection.selected_word_end, caret_idx);
			set_caret_line(line, false, true, 0, caret_idx);
			set_caret_column(beg, true, caret_idx);
		} else {
			carets.write[caret_idx].selection.selecting_column = carets[caret_idx].selection.selected_word_beg;
			select(get_selection_line(caret_idx), carets[caret_idx].selection.selected_word_beg, line, end, caret_idx);
			set_caret_line(get_selection_to_line(caret_idx), false, true, 0, caret_idx);
			set_caret_column(get_selection_to_column(caret_idx), true, caret_idx);
		}
	}
	if (DisplayServer::get_singleton()->has_feature(DisplayServer::FEATURE_CLIPBOARD_PRIMARY)) {
		DisplayServer::get_singleton()->clipboard_set_primary(get_selected_text());
	}
	queue_redraw();
	click_select_held->start();
	merge_overlapping_carets();
}
void TextEdit::_update_selection_mode_line() {