PSUseDeclaredVarsMoreThanAssignments is not aware of Pester's scoping

Steps to reproduce

Supposing a Pester Test file like below:

$here = $PsScriptRoot

Describe 'My Module' {

    BeforeAll { $module = Import-Module "$here\MyModule.psd1" }
    AfterAll  { $module | Remove-Module -Force }

    It 'can be loaded' {
        $module | Should Not Be $null
     }
}

Expected behavior

No warning on the $module variable, as it is used in the code below.

Actual behavior

Invoke-ScriptAnalyzer reports the following:

PSUseDeclaredVarsMoreThanAssignments  Warning  My.Tests.ps1 5  The variable 'module' is assigned but never used.

Environment data

> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      5.1.16299.251
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.16299.251
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

> (Get-Module -ListAvailable PSScriptAnalyzer).Version | ForEach-Object { $_.ToString() }

1.16.1
1.16.0
1.15.0
1.14.1
1.14.0
1.13.0
1.12.0
1.11.1
1.11.0
1.10.0
1.9.0
1.8.1
1.8.0
1.7.0
1.6.0
1.5.0
1.4.0
1.3.0
1.2.0
1.1.1
1.1.0
1.0.2
1.0.1
1.0

首先复现 Pester 示例并检查 PSUseDeclaredVarsMoreThanAssignments 规则，重点关注它如何跨越 BeforeAll、AfterAll 和 It 块跟踪变量。完成的标准是示例不再将 $module 报告为已赋值但未使用，同时该规则仍能识别真正未使用的赋值。