[CI] Fix minor dependency vulnerability, fix CLA job running when clo…

…sing a PR

- GitHub warns about an outdated dependency (idna Rust crate) being vulnerable.
  This is only used as a transitive dependency in a sample however – update
  Rust deps for the sample to fix this.
- The CLA check CI job ran when closing a PR so far, leading to a confusing
  comment when closing a PR that would not pass the CLA job even though the
  point of CLA passing is now moot. Accordingly, we should only run the CLA when
  opening or synchronizing a PR.

.github/workflows/cla.yml

@@ -3,7 +3,7 @@ on:
   issue_comment:
     types: [created]
   pull_request_target:
-    types: [opened,closed,synchronize]
+    types: [opened,synchronize]
   merge_group:
 
 jobs: