Fix #86, Removes extraneous boolean logic in concat command

[chillfig]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I signed and emailed the appropriate Contributor License Agreement to [email protected] and copied [email protected].

Describe the contribution

• Fixes FM_ChildConcatCmd - cyclomatic complexity of 17 #86
  • Removes boolean logic tracking file status which results in reduction of cyclomatic complexity to 9 from 17 by bundling logic in one single nested if/else according to file status.

Testing performed

• lcov
• build
• cert_testbed cFE_EVS_ConcatFilesCmd.json functional test successful

Expected behavior changes
No impact to behavior

System(s) tested on

• OS: Ubuntu 22.04

Additional context
Could be argued that the concat function is more readable as-is, but this way, the NASA recommendation of 15 max cyclomatic complexity per function is satisfied.

Third party code
N/A

Contributor Info - All information REQUIRED for consideration of pull request
Justin Figueroa, Vantage Systems