fix(i18n): display set(s) are two words for English messages.

platform/i18n/src/locales/en-US/Messages.json

@@ -1,15 +1,15 @@
 {
   "1": "No valid instances found in series.",
-  "2": "DisplaySet has missing position information.",
-  "3": "DisplaySet is not a reconstructable 3D volume.",
-  "4": "Multi frame displaySet don't have pixel measurement information.",
-  "5": "Multi frame displaySet don't have orientation information.",
-  "6": "Multi frame displaySet don't have position information.",
-  "7": "DisplaySet has missing frames.",
-  "8": "DisplaySet has irregular spacing.",
-  "9": "DisplaySet has inconsistent dimensions between frames.",
-  "10": "DisplaySet has frames with inconsistent number of components.",
-  "11": "DisplaySet has frames with inconsistent orientations.",
-  "12": "DisplaySet has inconsistent position information.",
-  "13": "Unsupported displaySet."
+  "2": "Display set has missing position information.",
+  "3": "Display set is not a reconstructable 3D volume.",
+  "4": "Multi frame display sets do not have pixel measurement information.",
+  "5": "Multi frame display sets do not have orientation information.",
+  "6": "Multi frame display sets do not have position information.",
+  "7": "Display set has missing frames.",
+  "8": "Display set has irregular spacing.",
+  "9": "Display set has inconsistent dimensions between frames.",
+  "10": "Display set has frames with inconsistent number of components.",
+  "11": "Display set has frames with inconsistent orientations.",
+  "12": "Display set has inconsistent position information.",
+  "13": "Unsupported display set."
 }