Import-DbaParquet - Release the parquet file when the import is done

[andreasjordan]

Fixes #10542.

Import-DbaParquet kept the imported file locked after the import had finished, until the garbage collector
got around to finalizing the stream. How long that took varied from run to run, so a file could not reliably
be deleted, moved or overwritten right after importing it.

Cause

Get-ParquetReader opens a file stream and passes it to Parquet.NET without saying what should happen to it:

$reader = [Parquet.ParquetReader]::CreateAsync($stream).GetAwaiter().GetResult()

The overload in play is

CreateAsync(Stream input, ParquetOptions parquetOptions = null, Boolean leaveStreamOpen = True, CancellationToken cancellationToken)

leaveStreamOpen defaults to true, so disposing the reader deliberately leaves the stream open. The
command does dispose the reader, but nothing disposes the stream, so the handle lived until finalization.

leaveStreamOpen is now passed as false. All four arguments are passed explicitly because the stream
overload can only be selected by its full signature - with fewer arguments the string filePath overload is a
candidate too.

Testing

The symptom that made this visible was a test that could not clean up after itself: on PowerShell 7 the Pester
run failed in Remove-TestDrive with The process cannot access the file 'staging.ecdc_parquet_test.parquet' because it is being used by another process, while all 17 tests passed. It failed about every other run,
which is why it read as test flakiness rather than a defect.

	before	after
Import-DbaParquet.Tests.ps1 on PowerShell 7.4, five consecutive runs	failed ~1 in 2	5 of 5 clean
Import-DbaParquet.Tests.ps1 on Windows PowerShell 5.1	17 of 17	17 of 17

No test change was needed - the test was right and the command was wrong.

Note

This touches the same file as #10538 and #10541 but a different part of it. All three merge cleanly, verified
by merging them locally and running the tests above against the combination.

🤖 Generated with Claude Code