Fix scheduler num_steps for EfficientAD

[blaz-r]

📝 Description

• This PR adds guards and modifies code used in EfficientAD scheduler setup to now correctly determine number of steps. It now works regardless of the arguments (max_epochs, max_steps) provided.
• 🛠️ Fixes [Bug]: Training EfficientAd failed: ZeroDivisionError: integer division or modulo by zero #1679

✨ Changes

Select what type of change your PR is:

• 🐞 Bug fix (non-breaking change which fixes an issue)
• 🔨 Refactor (non-breaking change which refactors the code base)
• 🚀 New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🔒 Security update

✅ Checklist

Before you submit your pull request, please make sure you have completed the following steps:

• 📋 I have summarized my changes in the CHANGELOG and followed the guidelines for my type of change (skip for minor changes, documentation updates, and test enhancements).
• 📚 I have made the necessary updates to the documentation (if applicable).
• 🧪 I have written tests that support my changes and prove that my fix is effective or my feature works (if applicable).

[alexriedel1]

LGTM!

[samet-akcay]

lgtm, thanks!