add ut for containerd init

[CormickKneey]

Description

Related Issue

Motivation and Context

Screenshots (if appropriate)

[codecov]

Codecov Report

Attention: Patch coverage is 96.77419% with 2 lines in your changes missing coverage. Please review.

Project coverage is 33.17%. Comparing base (574f376) to head (63802b4).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ly-client-init/src/container_runtime/containerd.rs	96.77%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #859      +/-   ##
==========================================
+ Coverage   32.64%   33.17%   +0.53%     
==========================================
  Files          57       57              
  Lines        8712     8774      +62     
==========================================
+ Hits         2844     2911      +67     
+ Misses       5868     5863       -5     

Files with missing lines	Coverage Δ
...ly-client-init/src/container_runtime/containerd.rs	97.14% <96.77%> (+84.64%)	⬆️

---- 🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[gaius-qi]

LGTM