## Description 

This PR adds a new type-guard util called `isSuiChain` which is useful
for implementing dApp interfaces in wallets (see example below). The
Solana wallet-standard has an equivalent utility for this as well, and
it seems to be used commonly in open source wallet implementations.

<img width="841" alt="image"
src="https://github.com/MystenLabs/sui/assets/7453188/2f54e316-06ad-4547-8086-950fb983d787">

## Test Plan 
- Manual testing

---
If your changes are not user-facing and do not break anything, you can
skip the following section. Otherwise, please briefly describe what has
changed under the Release Notes section.

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

- [ ] protocol change
- [ ] 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