Merge #2854: [Qt] Don't always clear coin control

0a8163b Don't update coincontrol for same coin type (Alessandro Rezzi)

Pull request description:

  Another trivial bug fix:  On creating a transaction with the GUI don't clear the Coin Control if the user presses the "Transparent" button when the transaction is already set on "Transparent" and same for "Shielded" (see the picture)
  ![2023-04-21-132113_1366x768_scrot](https://user-images.githubusercontent.com/22001825/233624199-89a7bc2b-bbe2-4bf7-a549-d2b78a398577.png)

ACKs for top commit:
  Liquid369:
    tACK 0a8163b
  Fuzzbawls:
    ACK 0a8163b

Tree-SHA512: b87d756f9e3bd060372d554f1616e8823f8d284b67a83bcea51d1eeb72edb3b32621a91bfdad22363daedca6e605eee7dd2fa17ca5a623a1e1bded297a3ff35f

src/qt/pivx/send.cpp

@@ -783,11 +783,13 @@ void SendWidget::onCheckBoxChanged()
 
 void SendWidget::onPIVSelected(bool _isTransparent)
 {
-    isTransparent = _isTransparent;
-    resetChangeAddress();
-    resetCoinControl();
-    tryRefreshAmounts();
-    updateStyle(coinIcon);
+    if (isTransparent != _isTransparent) {
+        isTransparent = _isTransparent;
+        resetChangeAddress();
+        resetCoinControl();
+        tryRefreshAmounts();
+        updateStyle(coinIcon);
+    }
 }
 
 void SendWidget::onContactsClicked(SendMultiRow* entry)