[Icarus] No API for looping through every row of every page of a sheet

[thedax]

This makes reading certain sheets like the Item sheet more cumbersome due to having to use the raw Physis API.

[redstrate]

Thinking about this, we need to be able to not just iterate through the rows but subrows as well. Some sheets have a variable number of subrows (SwitchTalkVariation) that cannot be known ahead of time, so we need to be able to write something like this:

for row in &sheet.rows {
    for subrow in row.subrows.iter().rev() {
       ...
    }
}

[redstrate]

I added something like the above API, so you can write something like this psuedo-code:

let sheet = read_my_sheet();
for page in sheet.pages {
    for row in page {
         let ExcelRowKind::SingleRow(row) = row else {
             continue;
         };

         row.column_data[0];
    }
}

I can also add an iterator to ExcelSheet which just flattens the page iterators, but that seems like something more useful in Icarus. Tackling Icarus tomorrow, which shouldn't be too hard.

[redstrate]

Great news, #27 finishes this up where we can write code like this in Icarus:

let subrows = game_data.get_switch_talk_subrows(switch_talk_id);
// Higher subrows take precedence
for (_, row) in subrows.iter().rev() {
    let quest0 = row
        .Quest0()
        .into_u32()
        .copied()
        .map(adjust_quest_id)
        .unwrap_or_default();
...

And for just regular rows, I added flatten_subrows to the iterator allowing you to throw away subrow information:

for (id, row) in self.item_sheet.into_iter().flatten_subrows() {
    // If filter_group is 32, then this item is an Orchestrion Roll...
    if *row.FilterGroup().into_u8()? != 32 {
        continue;
    }

    if *row.AdditionalData().into_u32()? == orchestrion_id {
        return Some(id);
    }
}

I'm pretty happy with this as a first pass! 🎉