feat(ci): remove issues trigger from dispatch workflow

Author: DeanChensj

.github/workflows/gemini-dispatch.yml

@@ -52,9 +52,6 @@ jobs:
         github.event_name == 'pull_request' &&
         github.event.pull_request.head.repo.fork == false &&
         github.event.pull_request.draft == false
-      ) || (
-        github.event_name == 'issues' &&
-        contains(fromJSON('["opened", "reopened"]'), github.event.action)
       ) || (
         github.event.sender.type == 'User' &&
         startsWith(github.event.comment.body || github.event.review.body || github.event.issue.body, '@gemini-cli') &&