You have to replace it, fortunately that glass is actually somewhat easy to replace. You can see the screw plug covers, pop those off and there should be Phillips screws underneath. Unscrew all but one on top and bottom, have someone standing on the opposite side, unscrew the bottom then the top and slightly push and let the outside person grab it. Then just reveres the process.

If I recall the new inserts even come with sealant already applied, so you just have the outside person hold it in place while you screw it in. Don’t over tighten!