Bank transfer: Discourage payments before an order code exists (Z#23135042) (#3692)

* Bank transfer: Discourage payments befor an order code exists

* Update src/pretix/plugins/banktransfer/templates/pretixplugins/banktransfer/checkout_payment_form.html

Co-authored-by: Mira <weller@rami.io>

---------

Co-authored-by: Mira <weller@rami.io>

src/pretix/static/pretixpresale/scss/main.scss

@@ -482,6 +482,10 @@ h2 .label {
     }
 }
 
+.user-select-none {
+    user-select: none;
+}
+
 @for $i from 0 through 100 {
     .progress-bar-#{$i} { width: 1% * $i; }
 }