Fixed run_ui.py

[SidmoGoesBrrr]

Fixed the error that pops up when we only upload an image and click generate. This now asks the user to enter a valid news article.

[bahrom04]

if i enter news url and image for ex (two spider man) i got this error:
news url: https://edition.cnn.com/politics/live-news/trump-hush-money-trial-05-14-24/index.html
image: https://github.com/CodingWithLewis/MemeGenerator/blob/master/tests/image.jpg
openai.AuthenticationError: This app has encountered an error. The original error message is redacted to prevent data leaks. Full error details have been recorded in the logs (if you're on Streamlit Cloud, click on 'Manage app' in the lower right of your app).

[elebumm]

The code you put in has a syntax error. Perhaps just a simple if not news_article.strip(): would work?