Userland: Rely on a single authoritative source for the default PATH

Author: https://github.com/timschumi
Commit: 39a3775f48
Pull-request: https://github.com/SerenityOS/serenity/pull/14941
Reviewed-by: https://github.com/linusg

Userland/Shell/Shell.cpp

@@ -2189,7 +2189,7 @@ Shell::Shell()
             path.append({ path_env_ptr, strlen(path_env_ptr) });
         if (path.length())
             path.append(":"sv);
-        path.append("/usr/local/sbin:/usr/local/bin:/usr/bin:/bin"sv);
+        path.append(DEFAULT_PATH_SV);
         setenv("PATH", path.to_string().characters(), true);
     }