Fix crash when no Follow path target specified

Fixes a crash in the cloud renderer (it turns out, caused by the CPP runtime) when a Follow Path constraint has no target. Thanks for walking me through the backend tasks process and dependencies @mjtalbot!

Obviously it defeats the purpose of using follow path if you don't set a target, but still, we shouldn't crash.

Diffs=
baefd620c Fix crash when no Follow path target specified (#5706)

Co-authored-by: Philip Chung <philterdesign@gmail.com>

.rive_head

diff --git a/.rive_head b/.rive_head
index 8dc8e18..db6aa2b 100644
--- a/.rive_head
+++ b/.rive_head
@@ -1 +1 @@
-caed30e555827bd4f90339e85a0df7cc3a143c3a
+baefd620c53ec3e11584bf95c10efe1377348446

src/constraints/follow_path_constraint.cpp

diff --git a/src/constraints/follow_path_constraint.cpp b/src/constraints/follow_path_constraint.cpp
index 71f6459..af2664a 100644
--- a/src/constraints/follow_path_constraint.cpp
+++ b/src/constraints/follow_path_constraint.cpp
@@ -153,14 +153,16 @@
 
 StatusCode FollowPathConstraint::onAddedClean(CoreContext* context)
 {
-    Shape* shape = static_cast<Shape*>(m_Target);
-    shape->addDefaultPathSpace(PathSpace::FollowPath);
+    if (m_Target != nullptr && m_Target->is<Shape>())
+    {
+        Shape* shape = static_cast<Shape*>(m_Target);
+        shape->addDefaultPathSpace(PathSpace::FollowPath);
+    }
     return Super::onAddedClean(context);
 }
 
 void FollowPathConstraint::buildDependencies()
 {
-    assert(m_Target != nullptr);
     if (m_Target != nullptr && m_Target->is<Shape>()) // which should never happen
     {
         // Follow path should update after the target's path composer