if-else inside match arm always wraps

The following code

let prefix = match power {
    0 => "",
    1 => if binary { "K" } else { "k" },
    _ => &"MGTPEZYRQ"[power - 2..][..1],
};

is always formatting as the following

let prefix = match power {
    0 => "",
    1 => {
        if binary {
            "K"
        } else {
            "k"
        }
    }
    _ => &"MGTPEZYRQ"[power - 2..][..1],
};

There doesn't appear to be any option to keep the second match arm on a single line. (use_small_heuristics = "Max", max_width = 9999, match_arm_blocks = false and single_line_if_else_max_width = 9999 are not effective.)

I am testing with the following config with the nightly toolchain:

edition = "2024"
empty_item_single_line = true
fn_single_line = true
format_strings = true
group_imports = "StdExternalCrate"
hex_literal_case = "Lower"
imports_granularity = "Module"
match_arm_blocks = false
max_width = 9999
overflow_delimited_expr = true
reorder_impl_items = true
single_line_if_else_max_width = 9999
single_line_let_else_max_width = 9999
style_edition = "2024"
trailing_semicolon = false
unstable_features = true
use_field_init_shorthand = true
use_small_heuristics = "Max"
use_try_shorthand = true

The payload names no files or tests; first reproduce the provided Rust snippet with the nightly toolchain and configuration. Trace the rustfmt handling of match arms and if-else expressions, and consider the issue complete when the example preserves the second arm on one line without regressing related formatting behavior.