fix(security): apply proper PSScriptAnalyzer suppression pattern from PSWrapper

Apply the same SuppressMessageAttribute pattern used in Datto-DBPool_PSWrapper's
Get-DBPoolUser.ps1 function, which includes:
- Justification parameter with clear explanation
- Inline comment after the attribute

The temporary password in Initialize-DattoSecretStoreVault is safe because:
- It's randomly generated (32 characters)
- It's never stored or logged
- It's only used to satisfy SecretStore's initial setup requirement
- It's immediately replaced with no authentication

Author: cksapp

src/Initialize-RefreshDBPool.ps1

@@ -302,17 +302,23 @@ if (-not (Get-Module -Name Datto.DBPool.Refresh -Verbose:$false)) {
 
 
 # Set the environment variables for the Datto.DBPool.Refresh module
+# Initialize SecretStore with temporary password (required for initial setup, then switched to no authentication)
+function Initialize-DattoSecretStoreVault {
+    [Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSAvoidUsingConvertToSecureStringWithPlainText', '', Justification = "Temporary random password generated for initial SecretStore setup only. Never stored or logged.")]
+    # PSScriptAnalyzer - ignore creation of a SecureString using plain text rule
+    param()
+    
+    # Generate a random temporary password for initial SecretStore configuration
+    # This is immediately replaced with no authentication, but SecretStore requires a password for the initial setup
+    $tempPassword = -join ((65..90) + (97..122) + (48..57) | Get-Random -Count 32 | ForEach-Object { [char]$_ })
+    $secretStoreAuth = ConvertTo-SecureString $tempPassword -AsPlainText -Force
+    Set-SecretStoreConfiguration -Authentication Password -Password $secretStoreAuth -Confirm:$false
+    Set-SecretStoreConfiguration -Authentication none -Password $secretStoreAuth -Confirm:$false
+}
+
 try {
     if (-not (Get-SecretVault -Name Datto_SecretStore -ErrorAction SilentlyContinue -Verbose:$false)) {
-        # Generate a random temporary password for initial SecretStore configuration
-        # This is immediately replaced with no authentication, but SecretStore requires a password for the initial setup
-        $tempPassword = -join ((65..90) + (97..122) + (48..57) | Get-Random -Count 32 | ForEach-Object { [char]$_ })
-        # Suppress PSScriptAnalyzer warning: This is a randomly generated temporary password that is never stored
-        # and is only used to satisfy SecretStore's initial setup requirement before switching to no authentication
-        [Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSAvoidUsingConvertToSecureStringWithPlainText', '')]
-        $secretStoreAuth = ConvertTo-SecureString $tempPassword -AsPlainText -Force
-        Set-SecretStoreConfiguration -Authentication Password -Password $secretStoreAuth -Confirm:$false
-        Set-SecretStoreConfiguration -Authentication none -Password $secretStoreAuth -Confirm:$false
+        Initialize-DattoSecretStoreVault
         Add-DattoSecretStore -ErrorAction Stop
     }