[nrf noup] ci: Fix manifest-pr-skip

fixup! [nrf noup] ci: Enable action-manifest-pr

When the PR title or body contains "manifest-pr-skip", this action will
cancel itself, which results in a failure status. Use the same condition
to skip the whole workflow instead.

Signed-off-by: Grzegorz Swiderski <[email protected]>

Author: 57300

.github/workflows/manifest-PR.yml

@@ -4,14 +4,3 @@ on:
     types: [opened, synchronize, closed]
     branches:
       - main
-
-
-jobs:
-  call-manifest-pr-action:
-    runs-on: ubuntu-latest
-    steps:
-      - name: handle manifest PR
-        uses: nrfconnect/action-manifest-pr@main
-        with:
-          token: ${{ secrets.NCS_GITHUB_TOKEN }}
-          manifest-pr-title-details: ${{ github.event.pull_request.title }}