Add -UseMinimalHeader to Start-Transcript to minimize transcript header (#8402)

test/powershell/Modules/Microsoft.Powershell.Host/Start-Transcript.Tests.ps1

@@ -293,4 +293,28 @@ Describe "Start-Transcript, Stop-Transcript tests" -tags "CI" {
         $transcriptFilePath | Should -Exist
         $transcriptFilePath | Should -FileContentMatchMultiline $expectedContent
     }
+
+    It "UseMinimalHeader should reduce length of transcript header" {
+        $script = {
+            Start-Transcript -Path $transcriptFilePath
+            Stop-Transcript
+        }
+
+        $transcriptMinHeaderFilePath = $transcriptFilePath + "_minimal" 
+        $scriptMinHeader = {
+            Start-Transcript -Path $transcriptMinHeaderFilePath -UseMinimalHeader
+            Stop-Transcript
+        }
+
+        & $script
+        $transcriptFilePath | Should -Exist
+        $transcriptLength = (Get-Content -Path $transcriptFilePath -Raw).Length
+        
+        & $scriptMinHeader
+        $transcriptMinHeaderFilePath | Should -Exist
+        $transcriptMinHeaderLength = (Get-Content -Path $transcriptMinHeaderFilePath -Raw).Length
+        Remove-Item $transcriptMinHeaderFilePath -ErrorAction SilentlyContinue
+
+        $transcriptMinHeaderLength | Should -BeLessThan $transcriptLength
+    }
 }