[chore] fix githubgen allowlist adding Mrod1598 (#46244)

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#### Description

It seems @Mrod1598 was removed from the @open-telemetry organization.

This PR adds him to the allowlist to fix the CI.

See
https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/22244001752/job/64353928057?pr=46038

Signed-off-by: Paulo Dias <paulodias.gm@gmail.com>

Author: paulojmdias

cmd/githubgen/allowlist.txt

@@ -1,4 +1,5 @@
 KiranmayiB
 steven-freed
 garrett-splunk
-robertgustafsonsplunk
+robertgustafsonsplunk
+Mrod1598