fix: Add viewport constraint to dropdown heights and improve filter layout (#6358)

## Summary
Fixed dropdown components exceeding viewport on mobile/tablet
environments and improved workflow template selector dialog filter
layout.

https://github.com/Comfy-Org/ComfyUI_frontend/issues/6153

## Changes

### 1. Dropdown Height Constraints (MultiSelect & SingleSelect)
- Applied CSS `min()` function to use the smaller value between
`listMaxHeight` prop and 50% viewport height
- Ensures dropdowns don't overflow on devices with smaller viewport
heights like tablets and mobiles

### 2. Workflow Template Dialog Layout Improvements
- Grouped filters (Model, Use Case, License) on the left side
- Positioned Sort by option on the right for clearer visual hierarchy
- Used `justify-between` to place filters and sort options at opposite
ends

## Test Plan
- [ ] Verify dropdown works correctly on desktop browsers
- [ ] Confirm dropdown doesn't exceed 50vh on tablet viewport
- [ ] Confirm dropdown doesn't exceed 50vh on mobile viewport
- [ ] Check workflow template dialog filter/sort layout

## Screenshots
**Before**

[before.webm](https://github.com/user-attachments/assets/64b4b969-54ed-4463-abdf-0a4adef01e72)

**After**

[after.webm](https://github.com/user-attachments/assets/b38973e5-9e77-4882-adf8-306279d302e1)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

src/components/input/MultiSelect.vue

@@ -242,7 +242,7 @@ const pt = computed(() => ({
     )
   },
   listContainer: () => ({
-    style: { maxHeight: listMaxHeight },
+    style: { maxHeight: `min(${listMaxHeight}, 50vh)` },
     class: 'scrollbar-custom'
   }),
   list: {

src/components/input/SingleSelect.vue

@@ -158,7 +158,7 @@ const pt = computed(() => ({
     )
   },
   listContainer: () => ({
-    style: `max-height: ${listMaxHeight}`,
+    style: `max-height: min(${listMaxHeight}, 50vh)`,
     class: 'scrollbar-custom'
   }),
   list: {