table stub is right-aligned in RTF

[bzkrouse]

Prework

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Description

When a table with a left-aligned stub is output to RTF, the stub becomes right-aligned.

Reproducible example

exibble |>
     gt(
         rowname_col = "row",
         groupname_col = "group",
         row_group_as_column = TRUE
     ) |> 
    tab_style(
        style = list(cell_text(align = "left")),
        locations = list(cells_stub(), cells_row_groups())
    ) |> 
    gtsave("test.rtf")

[rich-iannone]

Now fixed with #2021.