bugfix: Mark CNoDestination and PubKeyDestination constructor explicit

This should fix the bug reported in
https://github.com/bitcoin/bitcoin/pull/28246#discussion_r1371640502,
which caused the GUI to not detect the destination type of recipients,
thus picking the wrong change destination type.

Also, add missing lifetimebound attribute to a getter method.

src/wallet/test/wallet_tests.cpp

@@ -605,7 +605,7 @@ BOOST_FIXTURE_TEST_CASE(ListCoinsTest, ListCoinsTestingSetup)
     // returns the coin associated with the change address underneath the
     // coinbaseKey pubkey, even though the change address has a different
     // pubkey.
-    AddTx(CRecipient{GetScriptForRawPubKey({}), 1 * COIN, /*subtract_fee=*/false});
+    AddTx(CRecipient{PubKeyDestination{{}}, 1 * COIN, /*subtract_fee=*/false});
     {
         LOCK(wallet->cs_wallet);
         list = ListCoins(*wallet);