v9 of the task to may import Pester v5 on a box with it installed

[kilasuit]

I noticed this in recent troubleshooting of an internal issue on our build boxes (we don't use the hosted agents)
Seems that this default value

AzureDevOpsExtension/Extension/PesterTask/PesterV9/Pester.ps1

Line 43 in a44ff1d

[string]$TargetPesterVersion = "latest"

will then have an impact on potentially importing pester at this point

AzureDevOpsExtension/Extension/PesterTask/PesterV9/Pester.ps1

Line 61 in a44ff1d

Import-Pester -Version $TargetPesterVersion

I propose to fix this with some additional defensive coding just to be sure that Pester v5 will never accidentally import