fix: avoid error when material type is unknown

not sure if this is a unique situation in my dev environment or
what..but i keep encountering this in dev, so might as well add it.
better safe than sorry

src/wuttafarm/web/util.py

@@ -81,7 +81,9 @@ def render_quantity_object(quantity):
     text = f"( {measure} ) {value} {unit}"
 
     if quantity["quantity_type_id"] == "material":
-        materials = ", ".join([mtype["name"] for mtype in quantity["material_types"]])
+        materials = ", ".join(
+            [mtype.get("name", "???") for mtype in quantity["material_types"]]
+        )
         return f"{materials} {text}"
 
     return text