copy: update WebGL support message

Part-of: <https://dev.funkwhale.audio/funkwhale/funkwhale/-/merge_requests/2346>

front/src/locales/en_US.json

@@ -179,7 +179,7 @@
       "message": {
         "automaticPlay": "The next track will play automatically in a few seconds…",
         "radio": "New tracks will be appended here automatically.",
-        "webglUnsupported": "Your browser does not support WebGL2 context"
+        "webglUnsupported": "Your browser doesn't appear to support WebGL2."
       },
       "warning": {
         "connectivity": "You may have a connectivity issue."