Fix AdminBin compilation: declare $in/$out before open3

Variables declared with 'my' inside open3() were scoped to that call,
causing 'Global symbol requires explicit package name' errors.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cpanel/admin/Gniza/Restore

@@ -87,7 +87,8 @@ sub _run_gniza {
     my (@args) = @_;
 
     my $err_fh = gensym;
-    my $pid = eval { open3(my $in, my $out, $err_fh, $GNIZA_BIN, @args) };
+    my ($in, $out);
+    my $pid = eval { open3($in, $out, $err_fh, $GNIZA_BIN, @args) };
     unless ($pid) {
         return (0, '', "Failed to execute gniza: $@");
     }