wallet: Use existing feerate instead of getting a new one
wallet: Use existing feerate instead of getting a new one

During each loop of CreateTransaction, instead of constantly getting a
new feerate, use the feerate that we have already fetched for all
fee calculations. Thix fixes a race condition where the feerate required
changes during each iteration of the loop.

This commit changes behavior as the "Fee estimation failed" error will
now take priority over "Signing transaction failed".

Github-Pull: #21083
Rebased-From: 1a6a0b0dfb90f9ebd4b86d7934c6aa5594974f5f

litecoin-project/litecoin,qtumproject/qtum,rnicoll/dogecoin,litecoin-project/litecoin,litecoin-project/litecoin,rnicoll/dogecoin,qtumproject/qtum,litecoin-project/litecoin,litecoin-project/litecoin,rnicoll/dogecoin,litecoin-project/litecoin,qtumproject/qtum,qtumproject/qtum,qtumproject/qtum,qtumproject/qtum,qtumproject/qtum,rnicoll/dogecoin,rnicoll/dogecoin