Possible privacy leakage due to ordered transaction inputs

[yixiao5428]

This is a security vulnerability. The wallet uses ordered inputs of transactions (src/wallet/wallet.cpp, line 2766 - 2772), which may incur privacy risks like fingerprinting the wallet to observers.

A possible solution is to clear the original order, shuffle it, and push back the new order before signing the transaction.

Similar fix from Bitcoin: https://github.com/bitcoin/bitcoin/commit/2fb9c1e6681370478e24a19172ed6d78d95d50d3.

Reported by 6004ed5feaa31ae9df36b5dbc60f0fa53255a5fb734334082c6d202405fc738c.