fix get_fee_estimate assertion (#20211)

fix get_fee_estimate

Author: almogdepaz

chia/full_node/full_node_rpc_api.py

@@ -998,7 +998,7 @@ async def get_fee_estimate(self, request: dict[str, Any]) -> dict[str, Any]:
 
         if peak is None:
             peak_height = uint32(0)
-            last_peak_timestamp = uint64(0)
+            last_peak_timestamp: Optional[uint64] = uint64(0)
             last_block_cost = 0
             fee_rate_last_block = 0.0
             last_tx_block_fees = uint64(0)
@@ -1011,7 +1011,6 @@ async def get_fee_estimate(self, request: dict[str, Any]) -> dict[str, Any]:
             while last_tx_block is None or last_peak_timestamp is None:
                 peak_with_timestamp -= 1
                 last_tx_block = self.service.blockchain.height_to_block_record(peak_with_timestamp)
-                assert last_tx_block.timestamp is not None  # mypy
                 last_peak_timestamp = last_tx_block.timestamp
 
             assert last_tx_block is not None  # mypy