Fix --exit-on-fail when installing custom node.

[robinjhuang]

Previously, the --exit-on-fail didn't work when installing custom node because the cm-cli-util caught the error and just prints an error message.

comfy-cli  (rh-exiton-fail) % comfy node install comfyui-essentials --exit-on-fail         
Execute from: /Users/junhanhuang/Documents/cloud/services/inference/comfyui
Command: ['/Users/junhanhuang/Documents/comfy-cli/.venv/bin/python3', 
'/Users/junhanhuang/Documents/cloud/services/inference/comfyui/custom_nodes/C
omfyUI-Manager/cm-cli.py', 'install', '--exit-on-fail', 'comfyui-essentials']
FETCH DATA from: 
/Users/junhanhuang/Documents/cloud/services/inference/comfyui/user/default/Co
mfyUI-Manager/cache/1514988643_custom-node-list.json [DONE]
install_node exit on fail:True...
FETCH DATA from: 
/Users/junhanhuang/Documents/cloud/services/inference/comfyui/user/default/Co
mfyUI-Manager/cache/1514988643_custom-node-list.json [DONE]
ERROR: An error occurred while installing 'comfyui-essentials'.
Node 'comfyui-essentials@unknown' not found in 

[codecov]

Codecov Report

❌ Patch coverage is 25.00000% with 9 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
comfy_cli/command/custom_nodes/cm_cli_util.py	14.28%	6 Missing ⚠️
comfy_cli/command/custom_nodes/command.py	40.00%	3 Missing ⚠️

@@            Coverage Diff             @@
##             main     #317      +/-   ##
==========================================
- Coverage   50.84%   50.72%   -0.12%     
==========================================
  Files          32       32              
  Lines        3436     3446      +10     
==========================================
+ Hits         1747     1748       +1     
- Misses       1689     1698       +9     

Files with missing lines	Coverage Δ
comfy_cli/command/custom_nodes/command.py	40.05% <40.00%> (-0.16%)	⬇️
comfy_cli/command/custom_nodes/cm_cli_util.py	22.80% <14.28%> (-2.69%)	⬇️

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[bigcat88]

lgtm, I'll add a test for this in a separate PR later