Remove release/5.0 Dependabot config (#41541)

.github/dependabot.yml

@@ -50,18 +50,6 @@ updates:
     labels:
       - area-infrastructure
     target-branch: "release/3.1"
-  - package-ecosystem: "gitsubmodule"
-    directory: "/"
-    schedule:
-      interval: "monthly"
-    allow:
-      - dependency-type: "all"
-    commit-message:
-      prefix: "[release/5.0] "
-      include: scope
-    labels:
-      - area-infrastructure
-    target-branch: "release/5.0"
   - package-ecosystem: "gitsubmodule"
     directory: "/"
     schedule: