RVRNEXT-39 make main currency nullable

src/PersistentData/Model/Community.php

@@ -33,12 +33,12 @@ class Community extends ModelWithSlug
         $this->currency = $currency;
     }
 
-    public function setMainCurrency(Currency $mainCurrency): void
+    public function setMainCurrency(?Currency $mainCurrency): void
     {
         $this->mainCurrency = $mainCurrency;
     }
 
-    public function setMainCurrencyId(int $mainCurrencyId): void
+    public function setMainCurrencyId(?int $mainCurrencyId): void
     {
         $this->mainCurrencyId = $mainCurrencyId;
     }