[Bug]: Logo should be optional

[individual-it]

Is there an existing issue for this?

• I have searched for an existing issue

Describe the bug

If no logo is given in the metadata, the alt-text "Logo" is shown.
I think the logo should be optional, some presentations might not have one.

Steps To Reproduce

create a presentation with this content:

---
slide: title-content
presenter:  JankariTech Pvt. Ltd.
footer: Some bugs
---

# This has some bugs

## h2 Content
### h3 content

Expected Behavior

no logo should be displayed

Actual Behavior

the text "Logo" is displayed in the presentation

Examples, Code Samples, or Screenshots

No response

Environment

What browsers are you seeing the problem on?

No response