[MusicXML import] fix title frame position

In MuseScore 3.5, the title frame position is taken from the MusicXML file. In practice this means that files generated by Sibelius result in a title frame at the bottom instead of the top of the first page. All other MusicXML producers seem to put the title frame at the top.

Previous MuseScore versions always put the title frame at the top, which is consistent with MuseScore's default behaviour. This came up in https://musescore.org/en/node/309655.

Relates to #270643: [EPIC] MusicXML import/export issues

Options:
1: leave as is in 3.5
2: restore the pre-3.5 behaviour

Opinions are welcome.