Shell: Don't whine about tcsetpgrp() failing

We intentionally skimp out on checking isatty() before them to cut down
on syscalls, so we should also accept the errors and just let them be.
Closes #6471.

Userland/Shell/Shell.cpp

@@ -822,10 +822,12 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
             perror("setpgid");
 
         if (!m_is_subshell) {
-            if (tcsetpgrp(STDOUT_FILENO, pgid) != 0 && m_is_interactive)
-                perror("tcsetpgrp(OUT)");
-            if (tcsetpgrp(STDIN_FILENO, pgid) != 0 && m_is_interactive)
-                perror("tcsetpgrp(IN)");
+            // There's no reason to care about the errors here
+            // either we're in a tty, we're interactive, and this works
+            // or we're not, and it fails - in which case, we don't need
+            // stdin/stdout handoff to child processes anyway.
+            tcsetpgrp(STDOUT_FILENO, pgid);
+            tcsetpgrp(STDIN_FILENO, pgid);
         }
     }