Add session as a dependency of rocketchat:lib

[ziedmahdi]

@RocketChat/core

The package rocketchat:lib is using session in /packages/rocketchat-lib/client/CustomTranslations.js but it's not declared as a direct dependency.

Meteor.autorun(function() {
    // Re apply translations if tap language was changed
    Session.get(TAPi18n._loaded_lang_session_key);
    RocketChat.applyCustomTranslations();
});

This commit will add it as a dependency to let apps include rocketchat:lib with errors.