Improved create invite modal (#14151)

* FEATURE: Always show advanced invite options

The UI is more simple and more efficient than how it was when the
advanced options toggle was introduced. It does not make sense to keep
it anymore.

* UX: Minor copy edits

* UX: Merge expire invite controls

There were two controls in the create invite modal. One was a static
text that displayed how much time is left until the invite expires. The
other one was a datetime selector that set the time the invite expires.

This commit merges the two controls in a single one: staff users will
continue to see the datetime selector without the static text and
regular users will only see the static text because they cannot set
when the invite expires.

* UX: Remove invite link

It should only be visible after the invite was created.

config/locales/client.en.yml

@@ -1613,7 +1613,7 @@ en:
           new_title: "Create Invite"
           edit_title: "Edit Invite"
 
-          instructions: "Share this link to instantly grant access to this site"
+          instructions: "Share this link to instantly grant access to this site:"
           copy_link: "copy link"
           expires_in_time: "Expires in %{time}"
           expired_at_time: "Expired at %{time}"
@@ -1621,20 +1621,20 @@ en:
           show_advanced: "Show Advanced Options"
           hide_advanced: "Hide Advanced Options"
 
-          restrict_email: "Restrict to one email address"
+          restrict_email: "Restrict to email"
 
           max_redemptions_allowed: "Max uses"
 
           add_to_groups: "Add to groups"
-          invite_to_topic: "Arrive at this topic"
+          invite_to_topic: "Arrive at topic"
           expires_at: "Expire after"
           custom_message: "Optional personal message"
 
           send_invite_email: "Save and Send Email"
+          send_invite_email_instructions: "Restrict invite to email to send an invite email"
           save_invite: "Save Invite"
 
           invite_saved: "Invite saved."
-          invite_copied: "Invite link copied."
 
         bulk_invite:
           none: "No invitations to display on this page."

config/site_settings.yml

@@ -586,6 +586,7 @@ users:
     default: true
   invite_expiry_days:
     default: 30
+    client: true
     max: 36500
   invites_per_page:
     client: true