Fix tojson pair for 20 address (#1032)

* added gerald test address

* exception for 20 address

* lint

* remove comment

* Update packages/keyring/src/pair/index.ts

Co-authored-by: Jaco <jacogr@gmail.com>

Co-authored-by: Jaco <jacogr@gmail.com>

packages/keyring/src/pair/index.ts

@@ -176,8 +176,11 @@ export function createPair ({ toSS58, type }: Setup, { publicKey, secretKey }: P
     toJson: (passphrase?: string): KeyringPair$Json => {
       // NOTE: For ecdsa and ethereum, the publicKey cannot be extracted from the address. For these
       // pass the hex-encoded publicKey through to the address portion of the JSON (before decoding)
+      // unless the publicKey is already an address
       const address = ['ecdsa', 'ethereum'].includes(type)
-        ? u8aToHex(secp256k1Compress(publicKey))
+        ? publicKey.length === 20
+          ? u8aToHex(publicKey)
+          : u8aToHex(secp256k1Compress(publicKey))
         : encodeAddress();
 
       return pairToJson(type, { address, meta }, recode(passphrase), !!passphrase);