fix(magentic-one): Remove redundant exception raising in update_ledger

[r-bit-rry]

magentic-one, ledger orchestrator
update_ledger handles exception, and has a retry mechnism in place to allow up to 10 retries but will fail on the first since its reraising the JSON decoding error.

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[husseinmozannar]

Thank you for the PR! Made a minor fix and merged