wallet: move "use-only coinControl inputs" below the selected inputs lookup

Otherwise, RPC commands such as `walletcreatefundedpsbt` will not support the manual selection of locked, spent and externally added coins.

Full explanation is inside #25118 comments but brief summary is:

`vCoins` at `SelectCoins` time could not be containing the manually selected input because, even when they were selected by the user, the current `AvailableCoins` flow skips locked and spent coins.

Extra note: this is an intermediate step to unify the `fAllowOtherInputs`/`m_add_inputs` concepts. It will not be a problem anymore in the future when we finally decouple the wtx-outputs lookup process from `SelectCoins` and don't skip the user's manually selected coins in `AvailableCoins`.

Author: furszy

src/wallet/spend.cpp

@@ -433,23 +433,6 @@ std::optional<SelectionResult> SelectCoins(const CWallet& wallet, const std::vec
 
     OutputGroup preset_inputs(coin_selection_params);
 
-    // coin control -> return all selected outputs (we want all selected to go into the transaction for sure)
-    if (coin_control.HasSelected() && !coin_control.fAllowOtherInputs)
-    {
-        for (const COutput& out : vCoins) {
-            if (!out.spendable) continue;
-            /* Set ancestors and descendants to 0 as these don't matter for preset inputs as no actual selection is being done.
-             * positive_only is set to false because we want to include all preset inputs, even if they are dust.
-             */
-            preset_inputs.Insert(out, /*ancestors=*/ 0, /*descendants=*/ 0, /*positive_only=*/ false);
-        }
-        SelectionResult result(nTargetValue, SelectionAlgorithm::MANUAL);
-        result.AddInput(preset_inputs);
-        if (result.GetSelectedValue() < nTargetValue) return std::nullopt;
-        result.ComputeAndSetWaste(coin_selection_params.m_cost_of_change);
-        return result;
-    }
-
     // calculate value from preset inputs and store them
     std::set<COutPoint> preset_coins;
 
@@ -497,6 +480,15 @@ std::optional<SelectionResult> SelectCoins(const CWallet& wallet, const std::vec
         preset_inputs.Insert(output, /*ancestors=*/ 0, /*descendants=*/ 0, /*positive_only=*/ false);
     }
 
+    // coin control -> return all selected outputs (we want all selected to go into the transaction for sure)
+    if (coin_control.HasSelected() && !coin_control.fAllowOtherInputs) {
+        SelectionResult result(nTargetValue, SelectionAlgorithm::MANUAL);
+        result.AddInput(preset_inputs);
+        if (result.GetSelectedValue() < nTargetValue) return std::nullopt;
+        result.ComputeAndSetWaste(coin_selection_params.m_cost_of_change);
+        return result;
+    }
+
     // remove preset inputs from vCoins so that Coin Selection doesn't pick them.
     for (std::vector<COutput>::iterator it = vCoins.begin(); it != vCoins.end() && coin_control.HasSelected();)
     {