fix: Correct error variable check

[FelixTing]

fix: #5336

PR Checklist

Please check if your PR fulfills the following requirements:

• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• I am not introducing a new dependency (add notes below if you are)
• I have added unit tests for the new feature or bug fix (if not, why?)
• I have fully tested (add details below) this the new feature or bug fix (if not, why?)
• I have opened a PR for the related docs change (if not, why?)

Testing Instructions

Enable ExternalMQTT for core-command and query a device that doesn't exist. The errorCode in the response payload should be 1.

# Query
mosquitto_pub -t edgex/commandquery/request/test  \
  -m '{
    "apiVersion": "v3",
    "requestId": "e6e8a2f4-eb14-4649-9e2b-175247911369",
    "ContentType": "application/json",
    "queryParams": {
      "offset": "0",
      "limit": "20"
     }
  }'

# Response
edgex/commandquery/response {"apiVersion":"v3","receivedTopic":"edgex/commandquery/response","correlationID":"ccefa43c-1c27-4484-b227-b4f238b989f7","requestID":"e6e8a2f4-eb14-4649-9e2b-175247911369","errorCode":1,"payload":"failed to get commands by device name 'test': request failed, status code: 404, err: no device with name 'test' found","contentType":"text/plain"}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 21.17%. Comparing base (3b327d4) to head (de2d417).

Files with missing lines	Patch %	Lines
...nternal/core/command/controller/messaging/utils.go	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5337   +/-   ##
=======================================
  Coverage   21.17%   21.17%           
=======================================
  Files         285      285           
  Lines       20958    20958           
=======================================
  Hits         4438     4438           
  Misses      16167    16167           
  Partials      353      353           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[judehung]

LGTM