`KeyError: 'fixedColumns'` in specific circumstance when retrieving uploads about ytmusicapi

[apastel]

Google is definitely messing with this currently. Now instead of not including the fixedColumns object in the response, it's now included but the duration is set to ' ' which breaks the parser:

.venv/lib/python3.12/site-packages/ytmusicapi/mixins/uploads.py:59: in get_library_upload_songs
    songs = parse_uploaded_items(results["contents"])
.venv/lib/python3.12/site-packages/ytmusicapi/parsers/uploads.py:39: in parse_uploaded_items
    "duration_seconds": parse_duration(duration),
.venv/lib/python3.12/site-packages/ytmusicapi/parsers/_utils.py:67: in parse_duration
    seconds = sum(multiplier * int(time) for multiplier, time in mapped_increments)
E   ValueError: invalid literal for int() with base 10: ' '

And although I said that this only happens right after uploading a new song, I had it happen on a user that had about 10k uploaded songs that had been sitting there for years, so I guess it's possible for any uploaded song to have a blank duration.

If I have time I will contribute a PR that will probably look something like this to cover both cases if there are no fixedColums and if the duration is just whitespace or empty string:

def parse_uploaded_items(results):
...
...
        duration = None
        if "fixedColumns" in data:
            duration = get_fixed_column_item(data, 0)["text"]["runs"][0]["text"]

def parse_duration(duration):
    if not duration or not duration.strip():
        return None
    mapped_increments = zip([1, 60, 3600], reversed(duration.split(":")))
    seconds = sum(multiplier * int(time) for multiplier, time in mapped_increments)
    return seconds