Don't show backtraces as it disturbs journey tests

Byron · Byron · commit a71b6deccf4f · 2023-08-24T20:08:51.000+02:00
And we don't usually see things crashing like this anyway, so there
is no loss.
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -1,7 +1,6 @@
 name: ci
 
 env:
-  RUST_BACKTRACE: 1
   CARGO_TERM_COLOR: always
   CLICOLOR: 1
 
