Merge bitcoin/bitcoin#34483: refactor: Use SpanReader over DataStream

fa0677d131 refactor: Use SpanReader over DataStream (MarcoFalke)
fad3eb3956 refactor: Use SpanReader over DataStream (MarcoFalke)
fa06e26764 refactor: [qt] Use SpanReader to avoid two vector copies (MarcoFalke)
fabd4d2e2e refactor: Avoid UB in SpanReader::ignore (MarcoFalke)
fa20bc2ec2 refactor: Use empty() over eof() in the streams interface (MarcoFalke)
fa879db735 test: Read debug log for self-checking comment (MarcoFalke)

Pull request description:

  This changes all places, where possible, to use SpanReader over DataStream. This makes the code easier to read and reason about, because `SpanReader` can never write data. Also, the code should be minimally faster, because it avoids a full redundant copy of the whole vector of bytes.

ACKs for top commit:
  stickies-v:
    re-ACK fa0677d131
  achow101:
    ACK fa0677d131
  janb84:
    re ACK fa0677d131
  sipa:
    crACK fa0677d131

Tree-SHA512: 1d9f43fc6e71d481cf7b8f8457f479745ee331734649e9e2c2ab00ce5d317112796c77afc328612ed004e65ac5c16fc92279d760cfb012cfddce9098c4af810f

src/qt/recentrequeststablemodel.cpp

@@ -189,8 +189,7 @@ void RecentRequestsTableModel::addNewRequest(const SendCoinsRecipient &recipient
 // called from ctor when loading from wallet
 void RecentRequestsTableModel::addNewRequest(const std::string &recipient)
 {
-    std::vector<uint8_t> data(recipient.begin(), recipient.end());
-    DataStream ss{data};
+    SpanReader ss{MakeByteSpan(recipient)};
 
     RecentRequestEntry entry;
     ss >> entry;

src/qt/test/wallettests.cpp

@@ -364,7 +364,7 @@ void TestGUI(interfaces::Node& node, const std::shared_ptr<CWallet>& wallet)
     std::vector<std::string> requests = walletModel.wallet().getAddressReceiveRequests();
     QCOMPARE(requests.size(), size_t{1});
     RecentRequestEntry entry;
-    DataStream{MakeUCharSpan(requests[0])} >> entry;
+    SpanReader{MakeByteSpan(requests[0])} >> entry;
     QCOMPARE(entry.nVersion, int{1});
     QCOMPARE(entry.id, int64_t{1});
     QVERIFY(entry.date.isValid());