refactor(ui5-li): replace the usage of image property with image slot

[yanaminkova]

Removes the image property of the ui5-li and renames the imageContent slot to image.

BREAKING CHANGE: The image property of the ui5-li is removed and the imageContent slot is renamed to image.
If you have previously used the image property:

<ui5-li image="./img/HT-1022.jpg">Standard List Item</ui5-li>

or the imageContent slot:

<ui5-li> Avatar inside imageContent slot
	<ui5-avatar slot="imageContent" shape="Square" initials="ABC" color-scheme="Accent2"></ui5-avatar>
</ui5-li>

Now use image slot instead:

<ui5-li> Avatar inside image slot
	<ui5-avatar slot="image" shape="Square" initials="ABC" color-scheme="Accent2"></ui5-avatar>
</ui5-li>

Related to #8461, #7887, #9200

[yanaminkova]

This pull request is currently on hold pending the merge of changes to the SuggestionItem, which uses the image property of the ui5-list. Once those changes are merged, work on this PR will resume.

[ilhan007]

Not blocked anymore @yanaminkova @dobrinyonkov
#9092 is merged and now this could be continued

[yanaminkova]

Hello @SAP/ui5-webcomponents-topic-rd, @SAP/ui5-webcomponents-topic-rl,
this PR contains changes to samples owned by your teams. Could you please review it?
Thanks!

The requested changes have been implemented approved.

The requested changes have been implemented and approved.