Remove SBOM generation since it's now in delivery-platform (#32073)

.github/workflows/snyk-sbom.yml

@@ -1,11 +0,0 @@
-name: Snyk - Software Bill of Materials (SBOM)
-on:
-  release:
-    types: [published]
-
-jobs:
-  sbom:
-    permissions:
-      contents: write
-    uses: mattermost/actions-workflows/.github/workflows/snyk-sbom.yml@9f3b82abb56fb8327b6b6e2d3fc16b92e45120ba
-    secrets: inherit