Ensure File Does Not Exist (#12536)

* error out

* gaz

---------

Co-authored-by: james-prysm <90280386+james-prysm@users.noreply.github.com>

tools/interop/convert-keys/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
     importpath = "github.com/prysmaticlabs/prysm/v4/tools/interop/convert-keys",
     visibility = ["//visibility:public"],
     deps = [
+        "//config/params:go_default_library",
         "//tools/unencrypted-keys-gen/keygen:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@in_gopkg_yaml_v2//:go_default_library",

tools/interop/convert-keys/main.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/tools/unencrypted-keys-gen/keygen"
 	log "github.com/sirupsen/logrus"
 	"gopkg.in/yaml.v2"
@@ -52,7 +53,7 @@ func main() {
 		})
 	}
 
-	outFile, err := os.Create(os.Args[2])
+	outFile, err := os.OpenFile(os.Args[2], os.O_CREATE|os.O_EXCL, params.BeaconIoConfig().ReadWritePermissions)
 	if err != nil {
 		log.WithError(err).Fatalf("Failed to create file at %s", os.Args[2])
 	}