Prevent snapshot update workflow to run on main (#7842)

Turns out if you don't give the gh workflow dispatch a ref it runs it on
main, oops

.github/workflows/update_kittest_snapshots.yml

@@ -14,6 +14,7 @@ jobs:
   update-snapshots:
     name: Update snapshots from artifact
     runs-on: ubuntu-latest
+    if: github.ref_name != 'main' # We never want to update snapshots directly on main
     permissions:
       contents: write
 

tests/egui_tests/tests/snapshots/text_edit_halign.png

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:3f60036a5af9b376cbf1fefaf8088ce41cfd0c19ec16f02b1d8b98c3e987972e
-size 13276