fix: ipld not found errors are not 404s

gateway/errors.go

@@ -12,7 +12,6 @@ import (
 	"github.com/ipfs/boxo/gateway/assets"
 	"github.com/ipfs/boxo/path/resolver"
 	"github.com/ipfs/go-cid"
-	ipld "github.com/ipfs/go-ipld-format"
 	"github.com/ipld/go-ipld-prime/datamodel"
 )
 
@@ -178,10 +177,6 @@ func webError(w http.ResponseWriter, r *http.Request, c *Config, err error, defa
 }
 
 func isErrNotFound(err error) bool {
-	if ipld.IsNotFound(err) {
-		return true
-	}
-
 	// Checks if err is of a type that does not implement the .Is interface and
 	// cannot be directly compared to. Therefore, errors.Is cannot be used.
 	for {