fix: added missing hook_preamble() for powershell hook

[chawyehsu]

Close #2696
Fix #2651

Detailed in #2651 (comment)

micromamba 'shell' 'hook' -s 'powershell' generates,

before:

Import-Module "$Env:MAMBA_ROOT_PREFIX\condabin\Mamba.psm1" -ArgumentList $MambaModuleArgs

Remove-Variable MambaModuleArgs

after:

when changeps1 is set to true,

$MambaModuleArgs = @{ChangePs1 = $True}
Import-Module "$Env:MAMBA_ROOT_PREFIX\condabin\Mamba.psm1" -ArgumentList $MambaModuleArgs

Remove-Variable MambaModuleArgs

when changeps1 is set to false,

$MambaModuleArgs = @{ChangePs1 = $False}
Import-Module "$Env:MAMBA_ROOT_PREFIX\condabin\Mamba.psm1" -ArgumentList $MambaModuleArgs

Remove-Variable MambaModuleArgs

[AntoinePrv]

Thanks! Let me finish fixing the CI and re-run this.