XWIKI-22605: Solr re-indexes many documents after restarting on PostgreSQL

* Remove the emoji from the test as it causes a test failure on
  MySQL 8.4. While it would be good to test with an emoji, the emoji
  didn't cause any actual differences in test executions so far and thus
  doesn't seem worth the hassle of making sure we don't use it on MySQL
  8.4.

(cherry picked from commit 67b865fb)