Merge #16572: wallet: Fix Char as Bool in Wallet

2dbfb37b407ed23b517f507d78fb77334142dce5 Fix Char as Bool in interfaces (Jeremy Rubin)

Pull request description:

  In a few places in src/wallet/wallet.h, we use a char when semantically we want a bool.

  This is kind of an issue because it means we can unserialize the same transaction with different fFromMe flags (as differing chars) and evaluate the following section in wallet/wallet.cpp
  ```c++
          if (wtxIn.fFromMe && wtxIn.fFromMe != wtx.fFromMe)
           {
               wtx.fFromMe = wtxIn.fFromMe;
               fUpdated = true;
           }
  ```
  incorrectly (triggering an fUpdated where both fFromMe values represent true, via different chars).

  I don't think this is a vulnerability, but it's just a little messy and unsemantic, and could lead to issues with stored wtxIns not being findable in a map by their hash.

  The serialize/unserialize code for bool internally uses a char, so it should be safe to make this substitution.

  NOTE: Technically, this is a behavior change -- I haven't checked too closely that nowhere is depending on storing information in this char. Theoretically, this could break something because after this change a tx unserialized with such a char would preserve it's value, but now it is converted to a ~true~ canonical bool.

ACKs for top commit:
  achow101:
    Code review ACK 2dbfb37b407ed23b517f507d78fb77334142dce5
  meshcollider:
    Code review ACK 2dbfb37b407ed23b517f507d78fb77334142dce5

Tree-SHA512: 8c0dc9cf672aa2276c694facbf50febe7456eaa8bf2bd2504f81a61052264b8b30cdb5326e1936893adc3d33504667aee3c7e207a194c71d87b3e7b5fe199c9d

0 files changed, 0 insertions, 0 deletions