Update charts/vl3-slice-router pod spec to add pod and container level SecurityContexts

### 📜 Description

Review and update charts/vl3-slice-router pod spec to add pod and container level SecurityContexts

### 👟 Reproduction steps

Install kubeslice-worker

### 👍 Expected behavior

VL3-slice-router pod specs should have securitycontexts with correct permissions (min required permissions)

### 👎 Actual Behavior

VL3-slice-router pod specs should have securitycontexts with correct permissions (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

Start by locating the charts/vl3-slice-router pod specification in the repository and install kubeslice-worker to inspect the resulting VL3-slice-router pod. Review the required minimum permissions for pod- and container-level SecurityContexts; the work is done when the generated pod specs include both with correct permissions.

Written by the indexing model from the issue text.