Update upgrade_nonce_account

- Using array slices directly

Author: dedeleono

programs/system/src/instructions/advance_nonce_account.rs

@@ -38,11 +38,10 @@ impl AdvanceNonceAccount<'_> {
         ];
 
         // instruction data uses 4-byte LE discriminator expected by the system program
-        const DATA: [u8; 4] = [4, 0, 0, 0];
         let instruction = Instruction {
             program_id: &crate::ID,
             accounts: &account_metas,
-            data: &DATA,
+            data: &[4, 0, 0, 0],
         };
 
         invoke_signed(

programs/system/src/instructions/upgrade_nonce_account.rs

@@ -21,11 +21,11 @@ impl UpgradeNonceAccount<'_> {
         // account metadata
         let account_metas: [AccountMeta; 1] = [AccountMeta::writable(self.account.key())];
 
-        // instruction
+        // instruction data uses 4-byte LE discriminator expected by the system program
         let instruction = Instruction {
             program_id: &crate::ID,
             accounts: &account_metas,
-            data: &[12],
+            data: &[12, 0, 0, 0],
         };
 
         invoke(&instruction, &[self.account])