[Bug] Marketplace Partners section: Previous/Next buttons overlap content on mobile

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### Dify version

1.17.0

### Cloud or Self Hosted

Self Hosted (Source)

### Steps to reproduce

1. Open Dify on a mobile device (or Chrome DevTools → iPhone 14 Pro Max, 430px width)
2. Click "Marketplace" in the left sidebar
3. Scroll down to the "Partners" section
4. Observe the Previous (<) and Next (>) navigation arrows

### ✔️ Expected Behavior

The Previous/Next navigation buttons should be properly spaced, centered, and not overlap with the partner cards or surrounding content on mobile screens

### ❌ Actual Behavior

The navigation buttons overlap with the partner card content. They appear too close together, misaligned, and partially hidden on mobile screens.