improve output of sdnresource dump

[arudell]

Description

This pull request makes minor improvements to the SDN diagnostics scripts by enhancing logging and clarifying the handling of function output. The main changes focus on providing better feedback after resource dumps and ensuring that command outputs are not unnecessarily displayed.

Enhancements to resource dump feedback and output handling:

• Added a log message in Invoke-SdnResourceDump to indicate the number of files exported and the output directory, improving visibility into the results of the resource dump operation. (src/modules/SdnDiag.NetworkController.psm1)
• Suppressed unwanted output from Invoke-SdnResourceDump in Start-SdnDataCollection by assigning the result to $null, ensuring cleaner script output. (src/SdnDiagnostics.psm1)

Change type

• Bug fix (non-breaking change)
• Code style update (formatting, local variables)
• New Feature (non-breaking change that adds new functionality without impacting existing)
• Breaking change (fix or feature that may cause functionality impact)
• Other

Checklist:

• My code follows the style and contribution guidelines of this project.
• I have tested and validated my code changes.