graphql: add transaction signature values (#20623)

The feature update allows the GraphQL API endpoint to retrieve
transaction signature R,S,V parameters.

Co-authored-by: amitshah <amitshah0t7@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>

graphql/schema.go

@@ -115,6 +115,9 @@ const schema string = `
         # Logs is a list of log entries emitted by this transaction. If the
         # transaction has not yet been mined, this field will be null.
         logs: [Log!]
+        r: BigInt!
+        s: BigInt!
+        v: BigInt!
     }
 
     # BlockFilterCriteria encapsulates log filter criteria for a filter applied