add payments support to single bills

app/src/main/java/sh/sar/gridflow/PayWithoutAccountActivity.kt

@@ -129,8 +129,13 @@ class PayWithoutAccountActivity : AppCompatActivity() {
             if (bill.status == "paid") {
                 Toast.makeText(this, "This bill has already been paid", Toast.LENGTH_SHORT).show()
             } else {
-                // TODO: Navigate to payment flow
-                Toast.makeText(this, "Payment flow coming soon", Toast.LENGTH_SHORT).show()
+                // Navigate to PaymentReviewActivity for single bill
+                val intent = android.content.Intent(this, PaymentReviewActivity::class.java)
+                intent.putExtra("SINGLE_BILL_ID", bill.id)
+                intent.putExtra("SINGLE_BILL_AMOUNT", bill.billAmount)
+                intent.putExtra("SINGLE_BILL_NUMBER", bill.billNumber)
+                intent.putExtra("SINGLE_BILL_SUBSCRIPTION_ID", bill.subscription.id)
+                startActivity(intent)
             }
         }
     }