Fix for missing or invalid EDF channel labels (#13170)

[shiva78567]

Overview

Fixes #13170

Some EDF files were returning None or empty strings in the ch_names list, which breaks downstream functions. This PR adds a fallback mechanism that replaces missing labels with "CH###" and emits a warning.

What does this PR do?

• Adds a fix in EDF reader to replace None or "" channel names with "CH###" format.
• Emits a warning when such a case is encountered.
• Adds a test to confirm this behavior in test_edf.py.

Additional Notes

Please let me know if you'd like this to be tested with specific data.

[welcome]

Hello! 👋 Thanks for opening your first pull request here! ❤️ We will try to get back to you soon. 🚴

[larsoner]

Hmmm this doesn't seem like it'll fix the problem as it just creates a new file named None with a few lines of code. Do you plan on integrating this in the codebase in the right place?

[larsoner]

Closing due to non-response but feel free to reopen if you come back to this @shiva78567