feat: remove unwanted code

Author: lmcmz

Android/wallet/src/androidTest/java/com/flow/wallet/wallet/EthereumWalletTests.kt

@@ -171,7 +171,6 @@ class EthereumWalletTests {
         val expectedHash = HasherImpl.keccak256(output.encoded.toByteArray()).toHexString()
         assertEquals(expectedHash, output.preHash.toByteArray().toHexString())
         assertEquals(expectedHash, output.txId().toHexString())
-        assertEquals("0x$expectedHash", output.txIdHex())
     }
 
     @Test

Android/wallet/src/main/java/com/flow/wallet/wallet/EthereumSigningOutputExtensions.kt

@@ -1,7 +1,6 @@
 package com.flow.wallet.wallet
 
 import com.flow.wallet.crypto.HasherImpl
-import wallet.core.jni.HexCoding
 import wallet.core.jni.proto.Ethereum
 
 /**
@@ -15,10 +14,3 @@ fun Ethereum.SigningOutput.txId(): ByteArray {
     val computed = HasherImpl.keccak256(encoded.toByteArray())
     return computed
 }
-
-fun Ethereum.SigningOutput.txIdHex(): String {
-    val bytes = txId()
-    if (bytes.isEmpty()) return "0x"
-    return "0x${HexCoding.encode(bytes)}"
-}
-