Fix EU AI Act template: add missing category_file path

The EU AI Act template was missing the category_file path in the guardrail definition, causing the guardrail to fail silently - it would be created in the database but wouldn't load the YAML rules file.

Without the category_file, the guardrail has no actual blocking rules, so prompts like "social credit system" pass through even though they should be blocked.

Adds the category_file path pointing to the eu_ai_act_article5.yaml file so the guardrail can load its rules.

Tested:
- Before fix: "social credit system" → 200 OK (passes through)
- After fix: "social credit system" → 403 blocked (works correctly)

litellm/policy_templates_backup.json

@@ -790,6 +790,7 @@
           "categories": [
             {
               "category": "eu_ai_act_article5_prohibited_practices",
+              "category_file": "litellm/proxy/guardrails/guardrail_hooks/litellm_content_filter/policy_templates/eu_ai_act_article5.yaml",
               "enabled": true,
               "action": "BLOCK",
               "severity_threshold": "medium"

policy_templates.json

@@ -790,6 +790,7 @@
           "categories": [
             {
               "category": "eu_ai_act_article5_prohibited_practices",
+              "category_file": "litellm/proxy/guardrails/guardrail_hooks/litellm_content_filter/policy_templates/eu_ai_act_article5.yaml",
               "enabled": true,
               "action": "BLOCK",
               "severity_threshold": "medium"