Remove old style custom scripts (#17077)

* fix: Move Newsletter script from frappe to erpnext

* fix: Remove old style client scripts

* C-Form

* fix: Cost Center

* fix: Fiscal Year

* fix: Monthly Distribution

* fix: Payment Gateway Account

* fix: Pricing Rule

* fix: Missing semicolon

erpnext/hooks.py

@@ -24,7 +24,8 @@ web_include_css = "assets/css/erpnext-web.css"
 doctype_js = {
 	"Communication": "public/js/communication.js",
 	"Event": "public/js/event.js",
-	"Website Theme": "public/js/website_theme.js"
+	"Website Theme": "public/js/website_theme.js",
+	"Newsletter": "public/js/newsletter.js"
 }
 
 welcome_email = "erpnext.setup.utils.welcome_email"