chore: add locale string for a11y label

Author: geositta

app/components/UI/Perps/Views/PerpsMarketDetailsView/PerpsMarketDetailsView.tsx

@@ -1384,7 +1384,9 @@ const PerpsMarketDetailsView: React.FC<PerpsMarketDetailsViewProps> = () => {
                 size={ButtonIconSize.Md}
                 onPress={handleFullscreenChartOpen}
                 testID={`${PerpsMarketDetailsViewSelectorsIDs.HEADER}-fullscreen-button`}
-                accessibilityLabel="Fullscreen chart"
+                accessibilityLabel={strings(
+                  'perps.market_details.fullscreen_chart',
+                )}
               />
             </Box>
           </Box>

locales/languages/en.json

@@ -2303,7 +2303,8 @@
       "referral_code_text": "Use my referral code to earn extra rewards."
     },
     "market_details": {
-      "category_search": "Browse related markets"
+      "category_search": "Browse related markets",
+      "fullscreen_chart": "Fullscreen chart"
     }
   },
   "market_insights": {