Selectively ignore opponent's human player station april tag

We don't have the april tags set up for our auto testing, so don't rely
on that tag.

Change-Id: I93cf62ace8e478f16e364797c0b5f4495188b548
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/frc971/control_loops/drivetrain/localization/utils.cc b/frc971/control_loops/drivetrain/localization/utils.cc
index ff027d0..d9e239b 100644
--- a/frc971/control_loops/drivetrain/localization/utils.cc
+++ b/frc971/control_loops/drivetrain/localization/utils.cc
@@ -30,6 +30,14 @@
              : true;
 }
 
+aos::Alliance LocalizationUtils::Alliance() {
+  joystick_state_fetcher_.Fetch();
+  return (joystick_state_fetcher_.get() != nullptr)
+             ? joystick_state_fetcher_->alliance()
+             : aos::Alliance::kInvalid;
+
+}
+
 std::optional<aos::monotonic_clock::duration> LocalizationUtils::ClockOffset(
     std::string_view node) {
   std::optional<aos::monotonic_clock::duration> monotonic_offset;