Bug 1778460 - Disable mode 2.5 on Nightly, r=necko-reviewers,dragana

Differential Revision: https://phabricator.services.mozilla.com/D151236

modules/libpref/init/StaticPrefList.yaml

@@ -10803,7 +10803,7 @@
 # If true, don't fallback to native DNS upon network errors.
 - name: network.trr.strict_native_fallback
   type: RelaxedAtomicBool
-  value: @IS_NIGHTLY_BUILD@
+  value: false
   mirror: always
 
 # If true, we'll fallback to native if the retry also times out.