(GHA) Fix authorized_accounts parameter handler

Prior to this change, the `verification/authorization/v1` workflow
definition of the `authorized_accounts` parameter handler defined an
empty scriptblock for the `IfNullOrEmpty` key to indicate that
null/empty values are acceptable for this optional parameter. Instead,
it shouldn't define the `IfNullOrEmpty` key-value pair at all. The
`Get-ActionScriptParameter` helper function ignores null or empty
values when the `IfNullOrEmpty` key isn't defined.

This change removes the `IfNullOrEmpty` key-value pair from the
`authorized_accounts` parameter handler definition.

Author: michaeltlombardi

.github/actions/verification/authorization/v1/Parameters.psd1

@@ -32,11 +32,6 @@
     @{
       Name = 'authorized_accounts'
       Type = 'String[]'
-      IfNullOrEmpty = {
-          param($ErrorTarget)
-
-          # This parameter is optional, so don't error.
-      }
       Process = {
         param($Parameters, $Value, $ErrorTarget)