solana: Add support for cancelling mint authority transfer

Author: nvsriram

solana/programs/example-native-token-transfers/src/instructions/admin.rs

@@ -183,7 +183,7 @@ pub struct SetTokenAuthority<'info> {
     /// CHECK: The constraints enforce this is valid mint authority
     pub token_authority: UncheckedAccount<'info>,
 
-    /// CHECK: This account will be the signer in the [claim_token_authority] instruction.
+    /// CHECK: The rent payer of the [PendingTokenAuthority] storing this account will be the signer in the [claim_token_authority] instruction.
     pub new_authority: UncheckedAccount<'info>,
 }
 
@@ -277,7 +277,8 @@ pub struct ClaimTokenAuthority<'info> {
             || new_authority.key() == token_authority.key()
         ) @ NTTError::InvalidPendingTokenAuthority
     )]
-    pub new_authority: Signer<'info>,
+    /// CHECK: constraint ensures that this is the correct address
+    pub new_authority: UncheckedAccount<'info>,
 
     #[account(
         mut,

solana/ts/idl/3_0_0/json/example_native_token_transfers.json

@@ -837,7 +837,7 @@
         {
           "name": "newAuthority",
           "isMut": false,
-          "isSigner": true
+          "isSigner": false
         },
         {
           "name": "pendingTokenAuthority",

solana/ts/idl/3_0_0/ts/example_native_token_transfers.ts

@@ -837,7 +837,7 @@ export type ExampleNativeTokenTransfers = {
         {
           "name": "newAuthority",
           "isMut": false,
-          "isSigner": true
+          "isSigner": false
         },
         {
           "name": "pendingTokenAuthority",
@@ -3034,7 +3034,7 @@ export const IDL: ExampleNativeTokenTransfers = {
         {
           "name": "newAuthority",
           "isMut": false,
-          "isSigner": true
+          "isSigner": false
         },
         {
           "name": "pendingTokenAuthority",