Do not initialize Emoji plugins if its database is not available

[pomek]

Provide a description of the task

Shortly, when the EmojiDatabase could not fetch the resource from a server, Emoji* plugins should not be initialized because the editor has nothing to show.

Right now, it ends with an ugly error when opening a picker.

emojigridview.ts:216 Uncaught TypeError: Cannot read properties of undefined (reading 'map')
    at EmojiGridView._updateGrid (emojigridview.ts:216:1)
    at EmojiGridView.filter (emojigridview.ts:168:1)
    at EmojiSearchView.search (emojisearchview.ts:68:1)
    at EmojiPicker.showUI (emojipicker.ts:143:1)
    at ButtonView.<anonymous> (emojipicker.ts:168:1)
    at ButtonView.fire (emittermixin.ts:240:1)

EmojiMention does not display anything from the database but suggests using a picker that will not show anything more.

Definition of Ready

• Redesign internals of the Emoji feature #17758 needs to be merged.

Technical details

• ckeditor5/packages/ckeditor5-emoji/src/emojidatabase.ts

  Line 80 in f7577fc

  // TODO: Add error handling in case when a database is not loaded.

• ckeditor5/packages/ckeditor5-emoji/src/emojipicker.ts

  Line 96 in f7577fc

  // TODO: Add error handling if the database was not initialized properly.

• ckeditor5/packages/ckeditor5-emoji/src/emojimention.ts

  Line 180 in f7577fc

  // TODO: Add error handling if the database was not initialized properly.