Run snyk dependency checks on all active branches (elastic#132545) (elastic#132564)

Adds missing periodic runs of `uploadSnykDependencyGraph` 
task for `8.18`, `9.0` and `9.1` branches.

Author: slobodanadamovic

.buildkite/pipelines/periodic.template.yml

@@ -217,7 +217,7 @@ steps:
       image: family/elasticsearch-ubuntu-2404
       machineType: n2-standard-8
       buildDirectory: /dev/shm/bk
-    if: build.branch == "main" || build.branch == "8.19" || build.branch == "7.17"
+    if: build.branch == "main" || build.branch == "9.1" || build.branch == "9.0" || build.branch == "8.19" || build.branch == "8.18" || build.branch == "7.17"
   - label: check-branch-consistency
     command: .ci/scripts/run-gradle.sh branchConsistency
     timeout_in_minutes: 15

.buildkite/pipelines/periodic.yml

@@ -921,7 +921,7 @@ steps:
       image: family/elasticsearch-ubuntu-2404
       machineType: n2-standard-8
       buildDirectory: /dev/shm/bk
-    if: build.branch == "main" || build.branch == "8.19" || build.branch == "7.17"
+    if: build.branch == "main" || build.branch == "9.1" || build.branch == "9.0" || build.branch == "8.19" || build.branch == "8.18" || build.branch == "7.17"
   - label: check-branch-consistency
     command: .ci/scripts/run-gradle.sh branchConsistency
     timeout_in_minutes: 15