Margin is set on list item when creating list from indented paragraph

[Artur Delura]

1. Open editor with no content
2. Focus editor
3. Click few times "Increase indent"
4. Click "Insert/Remove ordered list"
5. Switch to source mode:

<ul>
	<li style="margin-left: 120px;">Foo</li>
	<li>Bar</li>
</ul>

Expected:

<ul style="margin-left: 120px;">
	<li>Foo</li>
	<li>Bar</li>
</ul>

#Reasoning

Paragraph's margin should be moved to ol/li when creating list, because this is where indent/outdent buttons add/remove margin when you have a caret in the first item of a list.

However, I'm not sure what if we're creating list out of few paragraphs when each have different margin. I think that in such case it's best to remove those margins and "normalize" the situation. Otherwise, we'd have to go crazy and e.g. create sublists based on indentation of following paragraphs, but that would be a waste of time and we don't know if user wanted to do that anyway.

Alternatively, we can simply remove all margins when creating list, because none of the solutions seem to be 100% correct. Everyone can have different idea about how that should work.

[Artur Delura]

Related: #11803

[Piotrek Koszuliński]

I rephrased the ticket, because the issue occurs earlier that previously described.