add SELEX file formatting restriction

[Xilorole]

Specify File Format for Selex Sequences

Description

We need to specify the file format for selex sequences to ensure proper handling and processing. This includes restricting the file extension both in the frontend and during the file upload process.

Expected Behavior

• Restrict file uploads to specific extensions using the accept attribute.
• Provide clear error messages when unsupported file types are uploaded.

Steps to Reproduce

1. Attempt to upload a file with an unsupported extension.
2. Observe the error thrown during file reading.

Proposed Solution

• Update the frontend to use the accept attribute to restrict file uploads to the allowed extensions.
• Implement error handling to provide user-friendly error messages when unsupported file types are uploaded.

Additional Context

• Reference to URL with the accept attribute documentation and examples: [URL]

Tasks

• Update frontend file input to include the accept attribute for selex sequence files.
• Implement error handling for unsupported file types.
• Test the file upload process with various file types to ensure proper functionality.