### 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
ERR_FAIL_INDEX(p_caret, carets.size());
	if (!selecting_enabled) {
		return;
	}
	p_from_line = CLAMP(p_from_line, 0, text.size() - 1);
	p_from_column = CLAMP(p_from_column, 0, text[p_from_line].length());
	p_to_line = CLAMP(p_to_line, 0, text.size() - 1);
	p_to_column = CLAMP(p_to_column, 0, text[p_to_line].length());
	carets.write[p_caret].selection.from_line = p_from_line;
	carets.write[p_caret].selection.from_column = p_from_column;
	carets.write[p_caret].selection.to_line = p_to_line;
	carets.write[p_caret].selection.to_column = p_to_column;
	carets.write[p_caret].selection.active = true;
	if (get_selection_from_line(p_caret) == get_selection_to_line(p_caret)) {
		if (get_selection_from_column(p_caret) == get_selection_to_column(p_caret)) {