`mise use` creates a new `.mise.toml` even if `mise.toml` already exists

Describe the bug mise use creates a new .mise.toml even if mise.toml already exists.

To Reproduce

Rename .mise.toml to mise.toml in the directory. (Ensure to delete .mise.toml.)
Run mise use python in the same directory.
.mise.toml is newly created.

e.g.

mkdir mise-test
cd mise-test
echo -e "[tools]\nnode = \"latest\"" >> mise.toml
cat mise.toml
# [tools]
# node = "latest"
mise use --verbose python
cat .mise.toml
# [tools]
# python = "latest"

Then, ls -a shows both mise.toml and .mise.toml.

Expected behavior python is written in already existing mise.toml instead of the new .mise.toml

Cause mise use seems only to look for MISE_DEFAULT_CONFIG_FILENAME, the env value, or the default .mise.toml. https://github.com/jdx/mise/blob/9a9924e6473036468176014fdac5e8e49ee8123e/src/cli/use.rs#L180-L196

I don't understand well about the codebase but it seems other commands refer to DEFAULT_CONFIG_FILENAMES in config/mod.rs. https://github.com/jdx/mise/blob/9a9924e6473036468176014fdac5e8e49ee8123e/src/config/mod.rs#L460-L500

Workaround Settings MISE_DEFAULT_CONFIG_FILENAME=mise.toml will fix the issue.

mise doctor output

version: 2024.5.23 linux-x64 (2024-05-27)
activated: yes
shims_on_path: yes

build_info:
  Target: x86_64-unknown-linux-gnu
  Features: DEFAULT, NATIVE_TLS
  Built: Mon, 27 May 2024 14:51:00 +0000
  Rust Version: rustc 1.78.0 (9b00956e5 2024-04-29) (Homebrew)
  Profile: release

shell:
  /bin/bash
  GNU bash, version 5.1.16(1)-release (x86_64-pc-linux-gnu)
  Copyright (C) 2020 Free Software Foundation, Inc.
  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

  This is free software; you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.

dirs:
  data: ~/.local/share/mise
  config: ~/.config/mise
  cache: ~/.cache/mise
  state: ~/.local/state/mise
  shims: ~/.local/share/mise/shims

config_files:
  ~/.config/mise/config.toml
  ~/GitHub/mise-test/mise.toml

backends:
  cargo
  core
  go
  npm
  pipx
  ubi

plugins:
  actionlint         https://github.com/crazy-matt/asdf-actionlint.git#f8df3cf
  bun                (core)
  deno               (core)
  erlang             (core)
  go                 (core)
  java               (core)
  markdownlint-cli2  https://github.com/paulo-ferraz-oliveira/asdf-markdownlint-cli2#3b733f6
  node               (core)
  python             (core)
  ruby               (core)
  rust               https://github.com/code-lever/asdf-rust.git#95acf4f
  shellcheck         https://github.com/luizm/asdf-shellcheck.git#780d78d
  shfmt              https://github.com/luizm/asdf-shfmt.git#a42c5ff
  yamlfmt            https://github.com/mise-plugins/asdf-yamlfmt.git#5f36f2e
  yamllint           https://github.com/ericcornelissen/asdf-yamllint.git#e8e1d29
  zig                (core)

toolset:
  node@22.2.0
  bun@1.1.10
  python@3.12.3
  rust@1.78.0
  npm:@biomejs/biome@1.7.4-nightly.125f34b

env_vars:
  MISE_SHELL=bash

settings:
  activate_aggressive = false
  all_compile = false
  always_keep_download = false
  always_keep_install = false
  asdf_compat = false
  cargo_binstall = true
  color = true
  disable_default_shorthands = false
  disable_tools = []
  experimental = true
  go_default_packages_file = "~/.default-go-packages"
  go_download_mirror = "https://dl.google.com/go"
  go_repo = "https://github.com/golang/go"
  go_set_gopath = false
  go_set_goroot = true
  go_skip_checksum = false
  jobs = 4
  legacy_version_file = true
  legacy_version_file_disable_tools = []
  node_compile = false
  not_found_auto_install = true
  paranoid = false
  plugin_autoupdate_last_check_duration = "7d"
  python_default_packages_file = "/home/risu/.default-python-packages"
  python_pyenv_repo = "https://github.com/pyenv/pyenv.git"
  raw = false
  trusted_config_paths = []
  quiet = false
  verbose = false
  yes = false
  ci = false
  debug = false
  trace = false
  log_level = "info"
  python_venv_auto_create = false

  [status]
  missing_tools = "if_other_versions_installed"
  show_env = false
  show_tools = false

No warnings found
No problems found

Additional context

[DEBUG] ARGS: mise use --verbose python
[DEBUG] Config {
    Config Files: [
        "~/GitHub/mise-test/mise.toml",
        "~/.config/mise/config.toml",
    ],
}
[DEBUG] Toolset (359.412µs): node@latest, bun@latest, python@latest, rust@latest, npm:@biomejs/biome@latest
[DEBUG] install_versions: python@latest
mise ~/GitHub/mise-test/.mise.toml tools: python@3.12.3

jdx / mise

`mise use` creates a new `.mise.toml` even if `mise.toml` already exists #2205