fix: Make plugin test resolve latest version

[maciektr]

Summary

If --asdf-tool-version=latest is passed to plugin test, it should resolve the version correctly, instead of passing latest directly.
This change mimics the one of the old bash plugin:

asdf/lib/commands/command-plugin-test.bash

Lines 129 to 138 in 31e8c93

	# Use the version passed in if it was set. Otherwise grab the latest
	# version from the versions list
	if [ -z "$tool_version" ] || [[ "$tool_version" == *"latest"* ]]; then
	version="$(latest_command "$plugin_name" "$(sed -e 's#latest##;s#^:##' <<<"$tool_version")")"
	if [ -z "$version" ]; then
	fail_test "could not get latest version"
	fi
	else
	version="$tool_version"
	fi

It also adds a test case to ensure correct behaviour of the changed code.

Fixes: #2193

Other Information

[Stratus3D]

This || resolved == "" check should not be needed.

[Copilot]

Pull request overview

This PR fixes asdf plugin test so that when --asdf-tool-version=latest (or latest:<query>) is provided, it resolves to an actual version (via the plugin’s latest-stable/list-all callbacks) instead of passing the literal string latest through to installation.

Changes:

• Resolve --asdf-tool-version latest / latest:<query> in plugin test using internal/versions.Latest.
• Add a Bats test covering the latest resolution behavior.
• Update the dummy plugin fixture to fail if it is asked to install a literal latest version, ensuring the test meaningfully validates the fix.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated no comments.

File	Description
internal/cli/cli.go	Adds latest/latest:<query> resolution logic in pluginTestCommand before installing.
test/plugin_test_command.bats	Adds a regression test asserting plugin test succeeds when --asdf-tool-version latest is provided.
test/fixtures/dummy_plugin/bin/install	Makes the dummy plugin installation fail on literal latest to catch regressions.

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[Stratus3D]

Thank you for this fix @maciektr ! I've been meaning to review your PR and just today hit this issue myself.