DEV: Remove unused strings (#20159)

This removes lots of unused strings. Some of them were never used and some of them weren't removed when features changed...

* `js.pause_notifications.remaining` was removed in 836cbfe7ae6a18cef15622a6e15ed62a3d21a3af
* Looks like `deleted` was added in 651cfba93fc708197d58ab21dc8110a5d86052fc but was never used
* Looks like `image` was removed in a9e502936fb87bf480eb2f38f76de408b3556408

config/locales/client.en.yml

@@ -4301,13 +4301,11 @@ en:
     pause_notifications:
       title: "Pause notifications for..."
       label: "Pause notifications"
-      remaining: "%{remaining} remaining"
       options:
         half_hour: "30 minutes"
         one_hour: "1 hour"
         two_hours: "2 hours"
         tomorrow: "Until tomorrow"
-        custom: "Custom"
       set_schedule: "Set a notification schedule"
 
     trust_levels:
@@ -5631,7 +5629,6 @@ en:
         show_admin_profile: "Admin"
         manage_user: "Manage user"
         show_public_profile: "Show Public Profile"
-        impersonate: "Impersonate"
         action_logs: "Action Logs"
         ip_lookup: "IP Lookup"
         log_out: "Log Out"

config/locales/server.en.yml

@@ -3574,9 +3574,6 @@ en:
       one: "Heads up: We send a maximum of %{count} daily email. Check the site to see the ones that might be held back."
       other: "Heads up: We send a maximum of %{count} daily emails. Check the site to see the ones that might be held back. PS thanks for being popular!"
     in_reply_to: "In Reply To"
-    unsubscribe:
-      title: "Unsubscribe"
-      description: "Not interested in getting these emails? No problem! Click below to unsubscribe instantly:"
 
     header_instructions: ""
     reply_by_email: "[Visit Topic](%{base_url}%{url}) or reply to this email to respond."
@@ -3905,7 +3902,6 @@ en:
       liked_received: "Likes Received"
       new_users: "New Users"
       popular_topics: "Popular Topics"
-      follow_topic: "Follow this topic"
       join_the_discussion: "Read More"
       popular_posts: "Popular Posts"
       more_new: "New for you"
@@ -4159,10 +4155,6 @@ en:
       ## [Welcome to %{title}](#welcome)
       An account is required. Please ask an existing member for an invite or log in to continue.
 
-  deleted: "deleted"
-
-  image: "image"
-
   upload:
     edit_reason: "downloaded local copies of images"
     unauthorized: "Sorry, the file you are trying to upload is not authorized (authorized extensions: %{authorized_extensions})."