GHSA-2gw2-qgjg-xh6p: Namada-apps allows Post-Genesis Validator Bypass

Ledger crash. A user is able to initialize a post-genesis validator with a negative commission rate using the --force flag. If this validator gets into the consensus set, then when computing PoS inflation inside fn update_rewards_products_and_mint_inflation, an instance of mul_floor will cause the return of an Err, which causes finalize_block to error.