fix crash (#3634)

src/state/governance/hooks.ts

@@ -113,6 +113,7 @@ interface FormattedProposalLog {
 const FOUR_BYTES_DIR: { [sig: string]: string } = {
   '0x5ef2c7f0': 'setSubnodeRecord(bytes32,bytes32,address,address,uint64)',
   '0x10f13a8c': 'setText(bytes32,string,string)',
+  '0xb4720477': 'sendMessageToChild(address,bytes)',
 }
 
 /**
@@ -181,7 +182,7 @@ function useFormattedProposalCreatedLogs(
             let types: string
             if (signature === '') {
               const fourbyte = calldata.slice(0, 10)
-              const sig = FOUR_BYTES_DIR[fourbyte]
+              const sig = FOUR_BYTES_DIR[fourbyte] ?? 'UNKNOWN()'
               if (!sig) throw new Error('Missing four byte sig')
               ;[name, types] = sig.substring(0, sig.length - 1).split('(')
               calldata = `0x${calldata.slice(10)}`