fix(ui5-li-custom): enable setting height of the custom content

[ilhan007]

Provide min-height and height: auto to the custom list item, so the consumers can set a custom height to their content.
Fixes: #310

[fifoosid]

I would go for height: 100%, because that way the bottom border will fall to the end of the list item

[ilhan007]

I will revisit it once again, as Martin also suggested that providing min-height makes it not 100% custom (someone may want to set smaller height) and I will consider this comment as well

[fifoosid]

I also thought about this case, but it becomes very difficult to handle, because the list can be SingleSelection or MultiSelection, which contains RadioButton or Checkbox, which are going to be cut.

[ilhan007]

valid point

[ilhan007]

I would go for height: 100%, because that way the bottom border will fall to the end of the list item

Applied with the latest commit.

old dated