Better handling of album comments (#1013)

* Change album comment behaviour

* Don't check first item

* Fix previously imported album comments.

* Remove song comments if album comment is present

ui/src/album/AlbumSongs.test.js

@@ -0,0 +1,24 @@
+import { removeAlbumCommentsFromSongs } from './AlbumSongs'
+
+describe('removeAlbumCommentsFromSongs', () => {
+  const data = { 1: { comment: 'one' }, 2: { comment: 'two' } }
+  it('does not remove song comments if album does not have comment', () => {
+    const album = { comment: '' }
+    removeAlbumCommentsFromSongs({ album, data })
+    expect(data['1'].comment).toEqual('one')
+    expect(data['2'].comment).toEqual('two')
+  })
+
+  it('removes song comments if album has comment', () => {
+    const album = { comment: 'test' }
+    removeAlbumCommentsFromSongs({ album, data })
+    expect(data['1'].comment).toEqual('')
+    expect(data['2'].comment).toEqual('')
+  })
+
+  it('does not crash if album and data arr not available', () => {
+    expect(() => {
+      removeAlbumCommentsFromSongs({})
+    }).not.toThrow()
+  })
+})