Switch to use our forked repo, ucsf-education/moodle-plagiarism_turni…

…tin to address failing tests in GHA.

- Using the same branch, UCSFCLE_403_STABLE, for our Moodle 4.4, since there has
  been no update since their v2024072401 release.

- Cherry-picked commit [23fb73b](catalyst/moodle-plagiarism_turnitin@23fb73b)
  that addressed turnitin/moodle-plagiarism_turnitin#683 and turnitin/moodle-plagiarism_turnitin#712.

.gitmodules

@@ -122,8 +122,8 @@
 	tag = v5.2.4
 [submodule "plagiarism/turnitin"]
 	path = plagiarism/turnitin
-	url = https://github.com/turnitin/moodle-plagiarism_turnitin
-	branch = master
+	url = https://github.com/ucsf-education/moodle-plagiarism_turnitin
+	branch = UCSFCLE_403_STABLE
 [submodule "question/type/wordselect"]
 	path = question/type/wordselect
 	url = https://github.com/marcusgreen/moodle-qtype_wordselect