accounts/abi/bind: fix gas price suggestion with pre EIP-1559 clients (#23102)

This fixes transaction sending in the case where an app using go-ethereum v1.10.4
is talking to a pre-EIP-1559 RPC node. In this case, the eth_maxPriorityFeePerGas
endpoint is not available and we can only rely on eth_gasPrice.

accounts/abi/bind/base.go

@@ -256,13 +256,10 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 			return nil, errors.New("maxFeePerGas or maxPriorityFeePerGas specified but london is not active yet")
 		}
 		if opts.GasPrice == nil {
-			price, err := c.transactor.SuggestGasTipCap(ensureContext(opts.Context))
+			price, err := c.transactor.SuggestGasPrice(ensureContext(opts.Context))
 			if err != nil {
 				return nil, err
 			}
-			if head.BaseFee != nil {
-				price.Add(price, head.BaseFee)
-			}
 			opts.GasPrice = price
 		}
 	}