chore: remove deprecated Approvals from Getting Started (#288)

Removes the Approvals page from the Getting Started section since those
commands have been deprecated.

Changes:
- Deleted `getting_started/approvals.md`
- Removed the entry from `config/navigation.json`
- Removed the leftover link in `labs/lab-05-runtime-controls.mdx`

<!-- mintlify-agent-attribution -->
---
Generated by Mintlify Agent.

Requested by: marko@kosli.com via Slack
Mintlify session: slack_1782312474.238029_C0AJTQ5633K

---------

Co-authored-by: mintlify[bot] <109931778+mintlify[bot]@users.noreply.github.com>

Author: mintlify[bot]

config/navigation.json

@@ -27,8 +27,7 @@
             "getting_started/attestations",
             "getting_started/environments",
             "getting_started/policies",
-            "getting_started/enforce_policies",
-            "getting_started/approvals"
+            "getting_started/enforce_policies"
           ]
         },
         {

config/redirects.json

@@ -1,4 +1,8 @@
 [
+  {
+    "source": "/getting_started/approvals",
+    "destination": "/getting_started/attestations"
+  },
   {
     "source": "/ci-defaults",
     "destination": "/integrations/ci_cd"

getting_started/approvals.md

@@ -233,7 +233,6 @@ You have full visibility and control over your software supply chain, from build
 
 - [Custom attestation types](/getting_started/attestations) for your specific tools
 - [Kubernetes environment reporting](/tutorials/report_k8s_envs) if you use K8s
-- [Approvals](/getting_started/approvals) for production deployment workflows
 
 **Further reading:**
 - [Environments](/getting_started/environments)