Copy-DbaLogin - Fix test to use Join-Path for cross-platform compatibility

The test was using Windows backslashes which failed on Linux CI runners.
Updated to use Join-Path which works on all platforms.

(do Copy-DbaLogin)

Co-authored-by: Chrissy LeMaire <[email protected]>

Author: github-actions[bot]

tests/Copy-DbaLogin.Tests.ps1

@@ -294,7 +294,8 @@ Describe $CommandName -Tag IntegrationTests {
             # This test verifies that the protection code exists and is properly structured
             # Manual testing should be performed in a domain environment to verify the protection works
 
-            $functionContent = Get-Content "$($TestConfig.ModuleBase)\public\Copy-DbaLogin.ps1" -Raw
+            $functionPath = Join-Path -Path $TestConfig.ModuleBase -ChildPath "public" | Join-Path -ChildPath "Copy-DbaLogin.ps1"
+            $functionContent = Get-Content $functionPath -Raw
             $functionContent | Should -BeLike '*LoginType -eq "WindowsGroup"*'
             $functionContent | Should -BeLike '*potential lockout risk*'
             $functionContent | Should -BeLike '*xp_logininfo*'