Separating tea bags on Shabbat

Hello Rabbi,

Some tea bags are sold in pairs, and before use, they must be separated from each other by tearing them in the designated place. Is it permissible to do so on Shabbat? Ostensibly, there is no cutting here, because it is not important to have an exact cut, although in practice it does happen (as with toilet paper). On the other hand, tearing is usually permitted in food packaging, as in date leggings, but here it is different: it is impossible to say that the packaging is invalid, because the goal is not to get the tea leaves out, but to separate the bag and use it.

What is the law?