core: use LCP specific message for NO_LCP (#14556)

core/lib/lh-error.js

@@ -23,6 +23,11 @@ const UIStrings = {
    * @example {NO_FCP} errorCode
    * */
   noFcp: 'The page did not paint any content. Please ensure you keep the browser window in the foreground during the load and try again. ({errorCode})',
+  /**
+   * @description Error message explaining that the Largest Contentful Paint metric was not seen during the page load.
+   * @example {NO_LCP} errorCode
+   * */
+  noLcp: 'The page did not display content that qualifies as a Largest Contentful Paint (LCP). Ensure the page has a valid LCP element and then try again. ({errorCode})',
   /**
    * @description Error message explaining that the page loaded too slowly to perform a Lighthouse run.
    * @example {NO_TTI_CPU_IDLE_PERIOD} errorCode
@@ -273,11 +278,11 @@ const ERRORS = {
   },
   NO_LCP: {
     code: 'NO_LCP',
-    message: UIStrings.badTraceRecording,
+    message: UIStrings.noLcp,
   },
   NO_LCP_ALL_FRAMES: {
     code: 'NO_LCP_ALL_FRAMES',
-    message: UIStrings.badTraceRecording,
+    message: UIStrings.noLcp,
   },
   UNSUPPORTED_OLD_CHROME: {
     code: 'UNSUPPORTED_OLD_CHROME',

shared/localization/locales/en-US.json

@@ -2384,6 +2384,9 @@
   "core/lib/lh-error.js | noFcp": {
     "message": "The page did not paint any content. Please ensure you keep the browser window in the foreground during the load and try again. ({errorCode})"
   },
+  "core/lib/lh-error.js | noLcp": {
+    "message": "The page did not display content that qualifies as a Largest Contentful Paint (LCP). Ensure the page has a valid LCP element and then try again. ({errorCode})"
+  },
   "core/lib/lh-error.js | notHtml": {
     "message": "The page provided is not HTML (served as MIME type {mimeType})."
   },

shared/localization/locales/en-XL.json

@@ -2384,6 +2384,9 @@
   "core/lib/lh-error.js | noFcp": {
     "message": "T̂h́ê ṕâǵê d́îd́ n̂ót̂ ṕâín̂t́ âńŷ ćôńt̂én̂t́. P̂ĺêáŝé êńŝúr̂é ŷóû ḱêép̂ t́ĥé b̂ŕôẃŝér̂ ẃîńd̂óŵ ín̂ t́ĥé f̂ór̂éĝŕôún̂d́ d̂úr̂ín̂ǵ t̂h́ê ĺôád̂ án̂d́ t̂ŕŷ áĝáîń. ({errorCode})"
   },
+  "core/lib/lh-error.js | noLcp": {
+    "message": "T̂h́ê ṕâǵê d́îd́ n̂ót̂ d́îśp̂ĺâý ĉón̂t́êńt̂ t́ĥát̂ q́ûál̂íf̂íêś âś â Ĺâŕĝéŝt́ Ĉón̂t́êńt̂f́ûĺ P̂áîńt̂ (ĹĈṔ). Êńŝúr̂é t̂h́ê ṕâǵê h́âś â v́âĺîd́ L̂ĆP̂ él̂ém̂én̂t́ âńd̂ t́ĥén̂ t́r̂ý âǵâín̂. ({errorCode})"
+  },
   "core/lib/lh-error.js | notHtml": {
     "message": "T̂h́ê ṕâǵê ṕr̂óv̂íd̂éd̂ íŝ ńôt́ ĤT́M̂Ĺ (ŝér̂v́êd́ âś M̂ÍM̂É t̂ýp̂é {mimeType})."
   },