Run agent test version bump on all active branches (#6309)

Before we had to manually trigger the update version automation for
all branches other than `main`.

.github/workflows/bump-agent-versions.yml

@@ -7,16 +7,31 @@ on:
     - cron: "0 0 * * *"
 
 jobs:
+  filter:
+    runs-on: ubuntu-latest
+    timeout-minutes: 1
+    outputs:
+      matrix: ${{ steps.generator.outputs.matrix }}
+    steps:
+      - id: generator
+        uses: elastic/oblt-actions/elastic/active-branches@v1
+        with:
+          exclude-branches: "7.17"
+
   update_versions:
     runs-on: ubuntu-latest
+    needs: [filter]
     permissions:
       contents: write
       pull-requests: write
+    strategy:
+      matrix: ${{ fromJson(needs.filter.outputs.matrix) }}
     steps:
-
       - name: Checkout
         uses: actions/checkout@v4
         with:
+          ref: "${{ matrix.branch }}"
+
           # no depth limit
           # so, we can generate snapshot versions based on release branches
           fetch-depth: 0