SimplePie: Fix support for feeds with XML preample + DTD (#7515)

Regression from https://github.com/FreshRSS/FreshRSS/pull/4374
fix: https://github.com/FreshRSS/FreshRSS/issues/7514
https://github.com/FreshRSS/simplepie/pull/35
Upstream PR: https://github.com/simplepie/simplepie/pull/914

lib/composer.json

@@ -14,7 +14,7 @@
         "marienfressinaud/lib_opml": "0.5.1",
         "phpgt/cssxpath": "v1.3.0",
         "phpmailer/phpmailer": "6.9.3",
-        "simplepie/simplepie": "dev-freshrss#d31582a14f027a3bb72079bbb52be788ed1c6f56"
+        "simplepie/simplepie": "dev-freshrss#2e668d7b1bc2787310b99d2fd59bfda96e31b6ae"
     },
     "config": {
         "sort-packages": true,