Replace usage of SpecialPage::getTitle with getPageTitle

Was deprecated in 1.23, see Icdcf5d5295ef5e7f08b1d403e0c123f78738fd40

Change-Id: I324a14f8977a101b7b7dba49a41ab7267b94b247
(cherry picked from commit 4a238dd822db1427ac9151e4a507a2854ba829ca)