enhancement: set recommend model to undefined if no model available

[urmauur]

Describe Your Changes

• set recommend model to undefined when model.length === 0

Fixes Issues

• Closes feat: Prompt user to download model, if no models are available #3537
• Closes #

Self Checklist

• Added relevant comments, esp in complex areas
• Updated docs (for bug fixes / features)
• Created issues for follow-up changes or refactoring needed

[github-actions]

Barecheck - Code coverage report

Total: 69.05%

Your code coverage diff: 0.00% ▴

Uncovered files and lines

File	Lines
web/hooks/useCreateNewThread.ts	44, 46, 51-52, 55-56, 163-164, 166-167, 174-175, 186, 195, 230, 233
web/hooks/useRecommendedModel.ts	36, 51-52, 54-55, 58, 60-62, 67, 69-71, 75, 79-81, 84-85, 88, 91-92, 95
web/screens/Thread/ThreadCenterPanel/ChatInput/index.tsx	81, 89, 95, 100, 113-117, 127-129, 134, 137, 163, 172, 178, 180, 245-247, 269-271, 300, 324, 376-378, 380-382, 384-386, 388-390, 403

[github-actions]

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