bugfix: Fix incorrect exception being thrown

Author: tvdijen

src/XML/ds/AbstractDSAKeyValueType.php

@@ -7,6 +7,7 @@
 use DOMElement;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XML\Exception\InvalidDOMElementException;
+use SimpleSAML\XML\Exception\MissingElementException;
 use SimpleSAML\XML\Exception\SchemaViolationException;
 use SimpleSAML\XML\Exception\TooManyElementsException;
 use SimpleSAML\XML\SchemaValidatableElementInterface;
@@ -153,7 +154,7 @@ public static function fromXML(DOMElement $xml): static
         Assert::same($xml->namespaceURI, static::NS, InvalidDOMElementException::class);
 
         $y = Y::getChildrenOfClass($xml);
-        Assert::minCount($y, 1, TooManyElementsException::class);
+        Assert::minCount($y, 1, MissingElementException::class);
         Assert::maxCount($y, 1, TooManyElementsException::class);
 
         $g = G::getChildrenOfClass($xml);