fix: Fix latest version check command

[toshimaru]

grep latest version using mise latest name.

mise install yarn:

  - type: mise_install
    name: yarn

2025-05-06 17:38:41 (9.14 MB/s) - 'yarn' saved [3010104]
mise yarn@4.9.1    ✓ installed
Finished with 0 on localhost
Running mise ls yarn | grep "$(mise latest yarn)" on localhost
yarn  4.9.1
Finished with 0 on localhost
[DONE] mise_install yarn on localhost

[Copilot]

Pull Request Overview

This PR fixes the latest version check command by updating the grep command to properly use the latest version when no specific version is provided.

• Updates the check method to conditionally use the version if set
• Replaces the original version_or_latest method with direct string interpolation in the command

Comments suppressed due to low confidence (1)

lib/serverkit/resources/mise_install.rb:21

• [nitpick] Consider using a consistent quoting style for the grep pattern across both branches of the conditional to enhance readability and reduce potential confusion.

          "$(mise latest #{name})"