move dollar sign inside brace for var in LogicException message

patter of dollar sign outside brace is deprecated as of php8.2

lib/Validator.php

@@ -122,7 +122,7 @@ public function validate(): array
             foreach($ruleIds as $rid) {
                 $rule = $this->getRule($rid);
                 if($rule === null) {
-                    throw new \LogicException("Trying to validate against a rule that doesn't exist (${rid})");
+                    throw new \LogicException("Trying to validate against a rule that doesn't exist ({$rid})");
                 }
 
                 // If prior rule check failure for field, short circuit if allowed