ESoCC: Required input error being shown the first time an input is being focused

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Observed behavior

After opening a side panel and focusing on a textbox for the first time, we see the "X field is required" error appear immediately, before we can make any changes.

https://github.com/user-attachments/assets/e9a46fba-5c97-4574-a649-53be273e311b

This is something that happens on the new Publish side panel on the version notes textarea, the language selector, and on the SubmitToCommunityLibrary side panel, on the description textarea.

Expected behavior

The error message should not appear right after we focus the fields for the first time, but only after we have already blurred the field. For example, in Kolibri, we have this:

https://github.com/user-attachments/assets/bdbb3756-78b0-4892-944e-cbf7c3104538

User-facing consequences

It could cause confusion and visual noise to the user.

Start with contentcuration/frontend/channelEdit/components/sidePanels/PublishSidePanel.vue and SubmitToCommunityLibrarySidePanel/index.vue, then compare their field validation behavior with Kolibri's FullNameTextbox.vue example. Reproduce the first-focus behavior in the side panels; done means required errors remain hidden until a field has been blurred.