zabbix: remove not needed vendorHash in versions file

pkgs/servers/monitoring/zabbix/agent2.nix

···
   {
     version,
     hash,
-    vendorHash ? throw "unsupported version ${version} for zabbix-agent2",
     ...
   }:
   buildGoModule {
···
 
     modRoot = "src/go";
 
-    inherit vendorHash;
+    vendorHash = null;
 
     nativeBuildInputs = [
       autoreconfHook

pkgs/servers/monitoring/zabbix/versions.nix

···
   v72 = generic {
     version = "7.2.5";
     hash = "sha256-DQGzk90isqYLNvs3qY/PEIHGg62Ygyot3YeUOhIAg54=";
-    vendorHash = null;
   };
   v70 = generic {
     version = "7.0.11";
     hash = "sha256-r9VNy3bRuFvJAL+ZQEbKjCAS3+AvetnWAwFjLxFVuGU=";
-    vendorHash = null;
   };
   v60 = generic {
     version = "6.0.36";
     hash = "sha256-Ne0OY6NGzTYOn3sDVd+5tfawBu5VBjxNRtlxasubGCk=";
-    vendorHash = null;
   };
 }