## Description 
* Adds clippy warning wherever `futures::executor::block_on` is used
* Area owners should address. Looks like mostly in indexer, narwhal,
sui-json, sui-json-rpc, sui-core

For more context see: https://github.com/MystenLabs/sui/pull/10910

## Test Plan 

N/A

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### Type of Change (Check all that apply)

- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes