Revert "ci/github-script/labels: close empty PRs"

This reverts commit 402b41c125.

GitHub' API repeatedly returns wrong data which causes closed PRs when
the changes had not been merged, yet.

We have closed a bit more than 100 PRs overall, most of them initially -
the feature is not really that important overall.

ci/github-script/bot.js

@@ -167,49 +167,6 @@ module.exports = async ({ github, context, core, dry }) => {
       getUser,
     })
 
-    // When the same change has already been merged to the target branch, a PR will still be
-    // open and display the same changes - but will not actually have any effect. This causes
-    // strange CI behavior, because the diff of the merge-commit is empty, no rebuilds will
-    // be detected, no maintainers pinged.
-    // We can just check the temporary merge commit, and if it's empty the PR can safely be
-    // closed - there are no further changes.
-    // We only do this for PRs, which are non-empty to start with. This avoids closing PRs
-    // which have been created with an empty commit for notification purposes, for example
-    // the yearly election notification for voters.
-    if (pull_request.merge_commit_sha && pull_request.changed_files > 0) {
-      const commit = (
-        await github.rest.repos.getCommit({
-          ...context.repo,
-          ref: pull_request.merge_commit_sha,
-        })
-      ).data
-
-      if (commit.files.length === 0) {
-        const body = [
-          `The diff for the temporary merge commit ${pull_request.merge_commit_sha} is empty.`,
-          'The changes in this PR have almost certainly already been merged to the target branch.',
-        ].join('\n')
-
-        core.info(`PR #${item.number}: closed`)
-
-        if (!dry) {
-          await github.rest.issues.createComment({
-            ...context.repo,
-            issue_number: pull_number,
-            body,
-          })
-
-          await github.rest.pulls.update({
-            ...context.repo,
-            pull_number,
-            state: 'closed',
-          })
-        }
-
-        return {}
-      }
-    }
-
     // Check for any human reviews other than the PR author, GitHub actions and other GitHub apps.
     // Accounts could be deleted as well, so don't count them.
     const reviews = (