ci: fix Comment PR Artifacts timeout and avoid duplicate build triggers

The Comment PR Artifacts workflow was timing out after ~12 minutes
(30 iterations × 10s sleep) while PR Build Validation runs regularly
take 17+ minutes, causing most PRs to show a failing CI check.

Changes:
- Increase comment workflow polling to 60 iterations × 20s sleep
  (~20 min max) so it reliably waits for the full build to complete.
- Remove the 'edited' trigger from pr-build.yml to prevent duplicate
  build runs when a PR title/body is edited. Editing a PR should not
  rebuild; only code changes (synchronize) and lifecycle events need
  builds. This also prevents the comment workflow from finding a
  newer in-progress run when a completed one already exists.

Co-authored-by: openhands <openhands@all-hands.dev>

Author: omercnet

.github/workflows/comment-pr-artifacts.yml

@@ -59,8 +59,11 @@ jobs:
 
             const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
 
+            const maxAttempts = 60;
+            const pollIntervalMs = 20_000;
+
             let matchedRun = null;
-            for (let attempt = 1; attempt <= 30; attempt += 1) {
+            for (let attempt = 1; attempt <= maxAttempts; attempt += 1) {
               const runs = await github.paginate(github.rest.actions.listWorkflowRuns, {
                 owner,
                 repo,
@@ -78,8 +81,8 @@ jobs:
                 break;
               }
 
-              core.info(`Waiting for PR Build Validation run for ${headSha} (attempt ${attempt}/30)`);
-              await sleep(10000);
+              core.info(`Waiting for PR Build Validation run for ${headSha} (attempt ${attempt}/${maxAttempts})`);
+              await sleep(pollIntervalMs);
             }
 
             if (!matchedRun) {

.github/workflows/pr-build.yml

@@ -4,7 +4,6 @@ on:
   pull_request:
     types:
       - opened
-      - edited
       - synchronize
       - reopened
       - ready_for_review