Convert EMotionFX runtime uint32 -> size_t

This allows the EMotionFX runtime to compile with `/we4267` enabled, which
emits a warning when converting from `size_t` to a smaller type. All tests
for the runtime have been updated accordingly, and they pass.

In instances where a range-for loop could be used, or a std algorithm, that
was used instead of using `size_t numItems = vec.size()` and a for loop.

Casts to `uint32` were removed where possible. Some places remain, like in
the file formats.

Signed-off-by: Chris Burel <burelc@amazon.com>

Gems/EMotionFX/Code/Tests/AnimGraphNodeProcessingTests.cpp

@@ -69,7 +69,7 @@ namespace EMotionFX
                 AnimGraphMotionNode* motionNode = aznew AnimGraphMotionNode();
                 motionNode->SetName(AZStd::string::format("MotionNode%zu", i).c_str());
                 m_blendTree->AddChildNode(motionNode);
-                m_blendNNode->AddConnection(motionNode, AnimGraphMotionNode::PORTID_OUTPUT_POSE, static_cast<uint16>(i));
+                m_blendNNode->AddConnection(motionNode, AnimGraphMotionNode::PORTID_OUTPUT_POSE, aznumeric_caster(i));
                 m_motionNodes.push_back(motionNode);
             }
             m_blendNNode->UpdateParamWeights();