Remove toLower on source (#31983)

Having this here breaks any source URLs that require case sensitivity.
(cherry picked from commit ed342e8ce3)

lib/ansible/modules/windows/win_chocolatey.ps1

@@ -39,10 +39,6 @@ $result = @{
     changed = $false
 }
 
-if ($source) {
-    $source = $source.Tolower()
-}
-
 if ($upgrade)
 {
     Add-DeprecationWarning -obj $result -message "Parameter upgrade=yes is replaced with state=latest" -version 2.6