[Docs]: Solve PKIX related issues in appsmith

### Problem Statement

Your API failed to execute:

```
org.springframework.web.reactive.function.client.WebClientRequestException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
{

```

### Use Cases / User query reference

We can add one more step in this [doc](https://community.appsmith.com/solution/how-do-i-export-custom-ca-certificate):

If the user can access the URL from browser. The user can go to terminal and if

`curl -v https://domain.com` gives a `200` response then the user can do the following

`openssl s_client -showcerts -connect :443 /dev/null | openssl x509 -outform PEM > ca_cert.pem
`

Verify if the ca-cert works using the following command

`curl --cacert https://domain/`

then copy the cert into `/appsmith-stacks/ca-certs/` and restart the container

### Audio/Video Recording

_No response_

### Product Requirements Document

_No response_

### Other Relevant Links

_No response_

### Checklist

- [X] Reviewed existing documentation to ensure this request is not duplicated.
- [X] Attached relevant media or supporting materials like links to the PRD, feature recordings, Slack or Discord links, and any other relevant resources.