[3.15] gh-90949: Fix copy-paste typo in pyexpat capsule API initialization (GH-151147) (#152088)

(cherry picked from commit 15696a6)

Co-authored-by: Stan Ulbrych <stan@python.org>

Author: miss-islington

Modules/pyexpat.c

@@ -2456,8 +2456,8 @@ pyexpat_exec(PyObject *mod)
     capi->SetBillionLaughsAttackProtectionActivationThreshold = XML_SetBillionLaughsAttackProtectionActivationThreshold;
     capi->SetBillionLaughsAttackProtectionMaximumAmplification = XML_SetBillionLaughsAttackProtectionMaximumAmplification;
 #else
-    capi->SetAllocTrackerActivationThreshold = NULL;
-    capi->SetAllocTrackerMaximumAmplification = NULL;
+    capi->SetBillionLaughsAttackProtectionActivationThreshold = NULL;
+    capi->SetBillionLaughsAttackProtectionMaximumAmplification = NULL;
 #endif
 
     /* export using capsule */