Bug Description:

Files can be added to the chat context by drag-dropping them into the chat view. The agent is informed about them via the contextFiles variable.

However the contextFiles variable often does not resolve properly, leaving the agent without context.

Steps to Reproduce:

1. Drag and Drop a file into chat view (without adding text to the chat input)
2. Execute @Coder What is wrong with this file
3. Observe by the answer and via the output channel that the files was added to the prompt via the contextFiles variable
4. Create a new chat session
5. Repeat step 1-2
6. Observe by the answer that the agent was not aware of the context. Check the output channel to see that the variable was not properly resolved

Additional Information

• Operating System: Ubuntu 24.04
• Theia Version: latest master (2402450)