chore: refactored timezone unexpected error handling

Author: andrepimpao

src/Rule/Timezone.php

@@ -17,7 +17,14 @@ public function __construct(
 
     public function assert(mixed $value, string $name): void
     {
-        if ($this->countryCode !== null) {
+        if ($this->timezoneGroup === \DateTimeZone::PER_COUNTRY) {
+            // Country code is required when using PER_COUNTRY timezone group
+            if ($this->countryCode === null) {
+                throw new UnexpectedValueException(
+                    'A country code is required when timezone group is \DateTimeZone::PER_COUNTRY.'
+                );
+            }
+
             // Normalize country code
             $this->countryCode = strtoupper($this->countryCode);
 
@@ -29,12 +36,6 @@ public function assert(mixed $value, string $name): void
             }
         }
 
-        if ($this->timezoneGroup === \DateTimeZone::PER_COUNTRY && $this->countryCode === null) {
-            throw new UnexpectedValueException(
-                'A country code must be given when timezone group is \DateTimeZone::PER_COUNTRY.'
-            );
-        }
-
         if (!\in_array($value, \DateTimeZone::listIdentifiers($this->timezoneGroup, $this->countryCode), true)) {
             throw new TimezoneException(
                 message: $this->message,