No else if in powershell (#7595)

Context
else if is a thing in powershell but only since about 3 months ago...which means that if you just updated powershell, the PR is unnecessary. This just means you don't have to be on the very latest version for it to work.

Testing
I used it

scripts/Deploy-MSBuild.ps1

@@ -60,8 +60,10 @@ if ($runtime -eq "Detect") {
         Write-Host "Detected path that does not look like an sdk. Writing .NET Framework assemblies."
     }
 }
-else if ($runtime -eq "Full") {
-    $runtime = "Desktop"
+else {
+    if ($runtime -eq "Full") {
+        $runtime = "Desktop"
+    }
 }
 
 if ($runtime -eq "Desktop") {