Add/Remove mark when region/zip is required

[luigifab]

Description

This PR fix display and validation when region/zip are required, for Customers addresses in backend.

Manual testing scenarios

In System / Configuration / General, set Allow Countries to USA, France, Ireland ; and remove France for State is required for.
Go to Customers, open any customer or add a new customer, then go to Addresses tab and add a new address.
Go to Sales, open any order, and try to edit Shipping or Billing address.

If you set country to usa, if you try to save the customer:

That's the truth.
Now if you set country to Ireland, if you try to save the customer:

That's wrong.
Now if you set country to France, if you try to save the customer:

That's the truth.
Apply the PR and try again.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All automated tests passed successfully (all builds are green)
• Add yourself to contributors list

[kiatng]

Tested & worked.

[github-actions]

Unit Test Results

1 files  ±0  1 suites  ±0   0s ⏱️ ±0s
0 tests ±0  0 ✔️ ±0  0 💤 ±0  0 ❌ ±0 
7 runs  ±0  5 ✔️ ±0  2 💤 ±0  0 ❌ ±0 

Results for commit 00748ce. ± Comparison against base commit 45db076.

[luigifab]

There is a little bug, on admin login page.
We need something like:

diff --git a/js/mage/adminhtml/form.js b/js/mage/adminhtml/form.js
@@ -609,4 +609,6 @@ function setPostcodeOptional(zipElement, country) {
     }
 }
 
-varienGlobalEvents.attachEventHandler("address_country_changed", onAddressCountryChanged);
+if (typeof varienGlobalEvents != 'undefined') {
+    varienGlobalEvents.attachEventHandler("address_country_changed", onAddressCountryChanged);
+}

[fballiano]

@luigifab created a PR for that