feat: make email optional for under-16 participants except applicant

src/BusProNet/DataProcessor/BookingPayloadBuilder.php

@@ -285,7 +285,7 @@ class BookingPayloadBuilder
             $participantData = [
                 '@id' => $index + 1,
                 'status' => self::DEFAULT_PARTICIPANT_STATUS,
-            ] + $this->buildPersonalDataPayload($participant, $applicantSource->email, true);
+            ] + $this->buildPersonalDataPayload($participant, true);
 
             // Add body dimensions
             if (null !== $participant->height) {
@@ -387,16 +387,12 @@ class BookingPayloadBuilder
      * Maps one person's personal data onto the payload shape shared by anmelder and teilnehmer.
      *
      * @param ParticipantDto $person               The applicant or participant to map
-     * @param string|null    $fallbackEmail        Used when the person has none of their own. BusPro
-     *                                             requires a Mail-Adresse for every participant once
-     *                                             a room is present and rejects the Anfrage with 650
-     *                                             otherwise, but accepts one shared with the Anmelder
      * @param bool           $alwaysIncludeAddress Participants always carry the anschrift structure
      *                                             even when empty; the anmelder only when set
      *
      * @return array<string, mixed>
      */
-    private function buildPersonalDataPayload(ParticipantDto $person, ?string $fallbackEmail = null, bool $alwaysIncludeAddress = false): array
+    private function buildPersonalDataPayload(ParticipantDto $person, bool $alwaysIncludeAddress = false): array
     {
         $data = [
             'name' => $person->lastName,
@@ -421,9 +417,9 @@ class BookingPayloadBuilder
             ];
         }
 
-        $email = null !== $person->email && '' !== trim($person->email)
-            ? $person->email
-            : $fallbackEmail;
+        // A participant may come without an email (under-16s, see ParticipantDto::$email), and
+        // BusPro accepts that, so a blank is sent as a blank rather than borrowing the applicant's.
+        $email = null !== $person->email && '' !== trim($person->email) ? $person->email : null;
 
         if (null !== $email || null !== $person->mobile) {
             $data['kommunikation'] = [];