[ci] Stop copying body over to backports in backport-fixup (#4005)

.github/workflows/backport-fixup.yml

@@ -1,5 +1,7 @@
 # Fixes up Mergify-created backport PRs to include necessary labels and other
-# information for release notes generation
+# information for release notes generation.
+# This action formerly copied over the PR body but it seems Mergify does that
+# itself now.
 
 name: Backport Fixup
 
@@ -66,25 +68,3 @@ jobs:
           # Long line but the paste joining must be done right away or we run into issues with spaces in labels
           LABELS=$(gh pr view --json labels --jq '.labels | .[].name | select(. != "Backported")' $ORIG_PR | paste -sd "," -)
           gh pr edit $BP_PR --add-label "$LABELS"
-      - name: Copy over body
-        env:
-          GH_TOKEN: ${{ github.token }}
-        run: |
-          BP_PR=${{ needs.resolve_prs.outputs.backport_pr }}
-          ORIG_PR=${{ needs.resolve_prs.outputs.original_pr }}
-
-          gh pr view --json body --jq '.body' $ORIG_PR > orig_body.txt
-          gh pr view --json body --jq '.body' $BP_PR > bp_body.txt
-
-          if grep -q '# Original PR Body' bp_body.txt; then
-            # Copy BP PR body but remove original PR body from bottom
-            sed '/# Original PR Body/q' bp_body.txt > new_bp_body.txt
-            echo "" >> new_bp_body.txt
-          else
-            cp bp_body.txt new_bp_body.txt
-            echo -e "\n----\n\n# Original PR Body\n" >> new_bp_body.txt
-          fi
-
-          cat orig_body.txt >> new_bp_body.txt
-
-          gh pr edit $BP_PR --body-file new_bp_body.txt