Update worker slice gateway pod spec with openvpn client container SecurityContext

### 📜 Description

Review and update worker slice gateway pod spec with openvpn client container SecurityContext (fix permissions)

### 👟 Reproduction steps

Create a slice with 2 clusters

### 👍 Expected behavior

Review the SecurityContext -too permissive - update with the min required permissions.

### 👎 Actual Behavior

Needs extra permissions - please review and update with min required permissions.

### 🐚 Relevant log output

_No response_

### Version

_No response_

### 🖥️ What operating system are you seeing the problem on?

Linux

### ✅ Proposed Solution

_No response_

### 👀 Have you spent some time to check if this issue has been raised before?

- [X] I checked and didn't find any similar issue

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct

Locate the worker slice gateway pod specification and inspect the OpenVPN client container's SecurityContext. Reproduce with a slice containing two clusters, then verify that the container has only the permissions required for the operation and that the slice is created successfully.

Written by the indexing model from the issue text.