Revert "Make UiTokenAmount::ui_amount a String (#15447)" (#15542)

This reverts commit d14374bc9f.

storage-proto/proto/solana.storage.confirmed_block.rs

@@ -104,8 +104,6 @@ pub struct UiTokenAmount {
     pub decimals: u32,
     #[prost(string, tag = "3")]
     pub amount: ::prost::alloc::string::String,
-    #[prost(string, tag = "4")]
-    pub ui_amount_string: ::prost::alloc::string::String,
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct Reward {

storage-proto/src/confirmed_block.proto

@@ -70,7 +70,6 @@ message UiTokenAmount {
     double ui_amount = 1;
     uint32 decimals = 2;
     string amount = 3;
-    string ui_amount_string = 4;
 }
 
 enum RewardType {

storage-proto/src/convert.rs

@@ -1,5 +1,5 @@
 use crate::StoredExtendedRewards;
-use solana_account_decoder::parse_token::{real_number_string_trimmed, UiTokenAmount};
+use solana_account_decoder::parse_token::UiTokenAmount;
 use solana_sdk::{
     hash::Hash,
     instruction::CompiledInstruction,
@@ -14,10 +14,7 @@ use solana_transaction_status::{
     ConfirmedBlock, InnerInstructions, Reward, RewardType, TransactionByAddrInfo,
     TransactionStatusMeta, TransactionTokenBalance, TransactionWithStatusMeta,
 };
-use std::{
-    convert::{TryFrom, TryInto},
-    str::FromStr,
-};
+use std::convert::{TryFrom, TryInto};
 
 pub mod generated {
     include!(concat!(
@@ -386,10 +383,9 @@ impl From<TransactionTokenBalance> for generated::TokenBalance {
             account_index: value.account_index as u32,
             mint: value.mint,
             ui_token_amount: Some(generated::UiTokenAmount {
+                ui_amount: value.ui_token_amount.ui_amount,
                 decimals: value.ui_token_amount.decimals as u32,
                 amount: value.ui_token_amount.amount,
-                ui_amount_string: value.ui_token_amount.ui_amount,
-                ..generated::UiTokenAmount::default()
             }),
         }
     }
@@ -402,14 +398,7 @@ impl From<generated::TokenBalance> for TransactionTokenBalance {
             account_index: value.account_index as u8,
             mint: value.mint,
             ui_token_amount: UiTokenAmount {
-                ui_amount: if !ui_token_amount.ui_amount_string.is_empty() {
-                    ui_token_amount.ui_amount_string
-                } else {
-                    real_number_string_trimmed(
-                        u64::from_str(&ui_token_amount.amount).unwrap_or(0),
-                        ui_token_amount.decimals as u8,
-                    )
-                },
+                ui_amount: ui_token_amount.ui_amount,
                 decimals: ui_token_amount.decimals as u8,
                 amount: ui_token_amount.amount,
             },