Remove development strings

## Issue
- Prevent translators from translating useless strings.

## Notes
- While 'Mark all as read' is technically valid, I've removed it since Notifications are not enabled in Desktop. When it is enabled, then we should include all the notification-related strings (there are a bunch).

static/app-strings.json

@@ -861,6 +861,7 @@
   "Tag Selection": "Tag Selection",
   "Select some tags to help us show you interesting things.": "Select some tags to help us show you interesting things.",
   "You are currently following %followingCount% tags": "You are currently following %followingCount% tags",
+  "You are currently following %followingCount% tag": "You are currently following %followingCount% tag",
   "Back": "Back",
   "Experimental Transcoding": "Experimental Transcoding",
   "A Folder containing FFmpeg": "A Folder containing FFmpeg",
@@ -1292,27 +1293,15 @@
   "%comment_count% comments - %comment_count_change% this week": "%comment_count% comments - %comment_count_change% this week",
   "Invite": "Invite",
   "Remove File": "Remove File",
-  "You are currently following %followingCount% tag": "You are currently following %followingCount% tag",
-  "DO a thing": "DO a thing",
-  "DO IT": "DO IT",
   "Not Yet": "Not Yet",
-  "I understand": "I understand",
-  "Enabling Sync": "Enabling Sync",
   "Enable Sync": "Enable Sync",
-  "Bring my stuff!": "Bring my stuff!",
   "Disable Sync": "Disable Sync",
-  "Enable": "Enable",
-  "Continuing will import the profile in your cloud wallet into your local wallet.": "Continuing will import the profile in your cloud wallet into your local wallet.",
-  "": "",
   "Getting your profiles...": "Getting your profiles...",
   "Enabling sync will switch to your cloud profile.": "Enabling sync will switch to your cloud profile.",
   "Disabling sync will switch to your local profile.": "Disabling sync will switch to your local profile.",
-  "Something went wrong...": "Something went wrong...",
   "To enable Sync, close LBRY completely and check 'Remember Password' during wallet unlock.": "To enable Sync, close LBRY completely and check 'Remember Password' during wallet unlock.",
-  "Something went wrong.": "Something went wrong.",
   "Something went wrong. Please %click_here% to learn about sync limitations.": "Something went wrong. Please %click_here% to learn about sync limitations.",
   "Buy LBC": "Buy LBC",
   "Continue...": "Continue...",
-  "Mark all as read": "Mark all as read",
   "--end--": "--end--"
 }