ci: remove deprecated submodule code (#20731)

docs/developing/guides/api/how-to-setup-api-in-a-local-instance.mdx

@@ -16,9 +16,6 @@ To test API in your local instance, you have the following pre-requisites:
         1a1f8138-0bfc-4f37-b4af-1e24fd145839
         ```
     </Step>
-    <Step title="Install API submodule">
-        Next, you need to install API submodule by following the instructions provided in [API submodule](/developing/local-development#api)
-    </Step>
     <Step title="Start development server and create API key">
         Start the cal.com server using `yarn dev` on localhost and create the test API keys by visiting `/settings/developer/api-keys`
     </Step>