remove experiment

pkgs/stack_trace/analysis_options.yaml

diff --git a/pkgs/stack_trace/analysis_options.yaml b/pkgs/stack_trace/analysis_options.yaml
index 2163f52..2e022f6 100644
--- a/pkgs/stack_trace/analysis_options.yaml
+++ b/pkgs/stack_trace/analysis_options.yaml
@@ -1,7 +1,5 @@
 include: package:pedantic/analysis_options.yaml
 analyzer:
-  enable-experiment:
-    - non-nullable
   strong-mode:
     implicit-casts: false