fix(ci): remove pull_request trigger from release-drafter workflow

The pull_request trigger causes release-drafter/release-drafter@v7 to fail
with 'Validation Failed: invalid field target_commitish' because it tries to
update the draft release using the PR merge ref (refs/pull/N/merge) as the
target commitish, which GitHub rejects.

Since the autolabeler feature is not in use, the pull_request trigger serves
no purpose. Removing it so the workflow only runs on push to main, which is
the correct behavior for maintaining the release draft.

Fixes recurring failures on PRs: run IDs 23369773059, 23369768998, 23111592904

Author: Ritchie

.github/workflows/release-drafter.yml

@@ -5,13 +5,9 @@ on:
     # branches to consider in the event; optional, defaults to all
     branches:
       - main
-  # pull_request event is required only for autolabeler
-  pull_request:
-    # Only following types are handled by the action, but one can default to all as well
-    types: [opened, reopened, synchronize]
-  # pull_request_target event is required for autolabeler to support PRs from forks
-  # pull_request_target:
-  #   types: [opened, reopened, synchronize]
+  # pull_request trigger removed: causes "invalid target_commitish" errors when
+  # release-drafter tries to update the draft release with a PR merge ref.
+  # Autolabeler is not in use; the push trigger is sufficient to keep the draft updated.
 
 permissions:
   contents: read
@@ -26,12 +22,7 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-      # (Optional) GitHub Enterprise requires GHE_HOST variable set
-      #- name: Set GHE_HOST
-      #  run: |
-      #    echo "GHE_HOST=${GITHUB_SERVER_URL##https:\/\/}" >> $GITHUB_ENV
-
-      # Drafts your next Release notes as Pull Requests are merged into "master"
+      # Drafts your next Release notes as Pull Requests are merged into "main"
       - uses: release-drafter/release-drafter@v7
         # (Optional) specify config name to use, relative to .github/. Default: release-drafter.yml
         # with: