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

…ethereum#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
  }
  }