improve output of sdnresource dump (#507)

# 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)
- [x] New Feature (non-breaking change that adds new functionality
without impacting existing)
- [ ] Breaking change (fix or feature that may cause functionality
impact)
- [ ] Other

# Checklist:
- [x] My code follows the style and contribution guidelines of this
project.
- [x] I have tested and validated my code changes.

Author: arudell

src/SdnDiagnostics.psm1

@@ -951,7 +951,7 @@ function Start-SdnDataCollection {
 
             $slbStateInfo = Get-SdnSlbStateInformation @ncRestParams
             $slbStateInfo | ConvertTo-Json -Depth 100 | Out-File "$($OutputDirectory.FullName)\SlbState.Json"
-            Invoke-SdnResourceDump @ncRestParams -OutputDirectory $OutputDirectory.FullName
+            $null = Invoke-SdnResourceDump @ncRestParams -OutputDirectory $OutputDirectory.FullName
             Get-SdnNetworkControllerState -NetworkController $NetworkController -OutputDirectory $OutputDirectory.FullName -Credential $Credential @restCredParam
         }
 

src/modules/SdnDiag.NetworkController.psm1

@@ -2459,6 +2459,11 @@ function Invoke-SdnResourceDump {
                 }
             }
         }
+
+        $files = Get-ChildItem -Path $outputDir.FullName
+        "Resource dump completed. {0} files exported to {1}" -f $files.Count, $outputDir.FullName | Trace-Output
+
+        return (Get-ChildItem -Path $outputDir.FullName)
     }
     catch {
         $_ | Trace-Exception