Fix WiFi (ZX or DPP) QR code parsing to ignore leading spaces

Increase robustness of QR code parsing: while leading spaces aren't
expected (or allowed) they are observed in the wild and can be safely
ignored.

Bug: 292331368
Test: validated that QR code with scan is now parsed correctly
Test: atest WifiQrCodeTest
Change-Id: Ifff79870bea2ec9924f7b2e8100c2c01fd350846

src/com/android/settings/wifi/dpp/WifiQrCode.java

@@ -160,8 +160,9 @@ public class WifiQrCode {
 
     private String getValueOrNull(List<String> keyValueList, String prefix) {
         for (String keyValue : keyValueList) {
-            if (keyValue.startsWith(prefix)) {
-                return  keyValue.substring(prefix.length());
+            String strippedKeyValue = keyValue.stripLeading();
+            if (strippedKeyValue.startsWith(prefix)) {
+                return strippedKeyValue.substring(prefix.length());
             }
         }