### 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 (placeholder_text == p_text) {
		return;
	}
	placeholder_text = p_text;
	_update_placeholder();
	queue_redraw();
}
String TextEdit::get_placeholder() const {
	return placeholder_text;
}
void TextEdit::set_line(int p_line, const String &p_new_text) {
	if (p_line < 0 || p_line >= text.size()) {
		return;
	}
	begin_complex_operation();
	_remove_text(p_line, 0, p_line, text[p_line].length());
	_insert_text(p_line, 0, p_new_text);
	for (int i = 0; i < carets.size(); i++) {
		if (get_caret_line(i) == p_line && get_caret_column(i) > p_new_text.length()) {
			set_caret_column(p_new_text.length(), false, i);
		}
		if (has_selection(i) && p_line == get_selection_to_line(i) && get_selection_to_column(i) > text[p_line].length()) {
			carets.write[i].selection.to_column = text[p_line].length();
		}
	}
	end_complex_operation();
}
String TextEdit::get_line(int p_line) const {