XLSX export of "X of Y" (eg. Month of Year) is formatted as date column

[flamber]

Describe the bug
XLSX export of "X of Y" (eg. Month of Year) is formatted as date column.

Workaround: In they XLSX viewer (Excel, Numbers, Calc), disable date formatting on the column.

To Reproduce

1. Custom question > Sample Dataset > Products
2. Count grouped by CreatedAt:MonthOfYear and Category
   
3. Export as XLSX
   
4. Export as CSV

Created At,Category,Count
1,Doohickey,2
1,Gadget,7
1,Gizmo,6
1,Widget,1
2,Doohickey,4
2,Gadget,5
2,Gizmo,4

Expected behavior
Preferably return the value similar to what is shown in Metabase (this might be tricky, especially with i18n), otherwise return the numeric value without date formatting.

Information about your Metabase Installation:
Tested 0.40.5 thru 0.41.1 - regression since 0.41.0

Additional context
Lightly related to #18572 and #18219

[nemanjaglumac]

@flamber this is what SheetJS sees for xlsx. Not sure which assertion would be appropriate because we're still not sure how will this be resolved. Any ideas?

{
    "A1": {
        "t": "s",
        "v": "Created At",
        "h": "Created At",
        "w": "Created At"
    },
    "B1": {
        "t": "s",
        "v": "Product → Category",
        "h": "Product → Category",
        "w": "Product → Category"
    },
    "C1": {
        "t": "s",
        "v": "Count",
        "h": "Count",
        "w": "Count"
    },
    "A2": {
        "t": "n",
        "v": 1,
        "w": "January 1, 1900, 12:00 AM"
    },
    "B2": {
        "t": "s",
        "v": "Doohickey",
        "h": "Doohickey",
        "w": "Doohickey"
    },
    "C2": {
        "t": "n",
        "v": 408,
        "w": "408"
    },
    "A3": {
        "t": "n",
        "v": 1,
        "w": "January 1, 1900, 12:00 AM"
    },
    "B3": {
        "t": "s",
        "v": "Gadget",
        "h": "Gadget",
        "w": "Gadget"
    },
    "C3": {
        "t": "n",
        "v": 452,
        "w": "452"
    },
}

[nemanjaglumac]

Also, please let me know if you'd like this covered for csv as well?

[flamber]

@nemanjaglumac I'm not sure if we're able to do similar translation as in-app, but otherwise it should return numeric value similar to CSV. And given the regression, then we should also cover CSV, so we don't regress there too.

[noahmoss]

Unassigning myself; when I started to dig into this it seemed pretty tricky to get exactly right. More of a mini project than a quick fix IMO