fix(metallb): deploy MetalLB with a non-BGP Cilium CNI (#692)

- Correct the Deploy metallb manifest/pool when condition so MetalLB is
  installed whenever kube-vip does not own the VIP range and Cilium BGP
  is disabled
- The previous guard (cilium_bgp is not defined or cilium_iface is not
  defined) skipped MetalLB whenever cilium_iface was set, breaking the
  cilium + MetalLB scenario
- Use cilium_bgp | default(false) | bool to stay safe when Cilium vars are
  not in scope (#644) while still deploying MetalLB for non-BGP Cilium
- Retry the converge-side MetalLB resource wait so a transient kube API
  ServiceUnavailable does not abort the converge play
- Add a regression test that evaluates both when conditions across flannel,
  calico, non-BGP cilium, BGP cilium, and kube-vip scenarios

ci: skip CI for Dependabot pull requests

- Add an actor guard to the CI workflow jobs so automatic Dependabot PRs
  do not consume the shared self-hosted runner
- Dependabot CI runs need maintainer approval instead of auto-running

.github/workflows/ci.yml

@@ -32,10 +32,13 @@ concurrency:
 
 jobs:
   pre:
+    if: github.actor != 'dependabot[bot]'
     uses: ./.github/workflows/cache.yml
     needs: [lint]
   lint:
+    if: github.actor != 'dependabot[bot]'
     uses: ./.github/workflows/lint.yml
   test:
+    if: github.actor != 'dependabot[bot]'
     uses: ./.github/workflows/test.yml
     needs: [pre, lint]