Remove bypass for dependabot on dependency-review check

The bypass `if` for dependabot PRs added in #19745 is failing `dependency-review` due
to this workflow effectively just proxying to another workflow in `shared-workflows`.
This is causing the workflow to not run at all, and since it's required, it's causing
dependabot PRs to not pass status checks. Remove the bypass for now to make checks
pass again.

.github/workflows/dependency-review.yaml

@@ -6,7 +6,6 @@ on:
 
 jobs:
   dependency-review:
-    if: ${{ !startsWith(github.head_ref, 'dependabot/') }}
     uses: gravitational/shared-workflows/.github/workflows/dependency-review.yaml@main
     permissions:
       contents: read