raw Commas
11
 1,1
111111
 1,1,1,1,1,1
1121
 1,1,2,1
122
 1,2,2
1111122
 1,1,1,1,1,2,2


Code:
// Table1
let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    Text = Table.TransformColumnTypes(Source,{{"raw", type text}}),
    Index = Table.AddIndexColumn(Text, "Index", 1, 1),
    SplitR = Table.ExpandListColumn(Table.TransformColumns(Index, {{"raw", Splitter.SplitTextByRepeatedLengths(1), let itemType = (type nullable text) meta [Serialized.Text = true] in type {itemType}}}), "raw"),
    Grp = Table.Group(SplitR, {"Index"}, {{"Count", each _, type table}}),
    List = Table.AddColumn(Grp, "Commas", each List.Buffer([Count][raw])),
    Ext = Table.TransformColumns(List, {"Commas", each Text.Combine(List.Transform(_, Text.From), ","), type text}),
    TSC = Table.SelectColumns(Ext,{"Commas"})
in
    TSC