Update on "[ET-VK] Add PushConstantDataInfo and vector to hold push constants data in DispatchNode."

This diff adds a new class called `PushConstantDataInfo` to the `DispatchNode` class in the Vulkan backend for Executorch.
This class represents a push constant data entry, which can either be a shared pointer to a tensor's uniform data with an attribute or data with a maximum size of 16 bytes.
The `write` method is also added to this class, which writes the data to a destination buffer.

Differential Revision: [D66796049](https://our.internmc.facebook.com/intern/diff/D66796049/)

[ghstack-poisoned]

Author: trivedivivek

backends/vulkan/runtime/graph/ops/DispatchNode.cpp

@@ -75,19 +75,21 @@ void DispatchNode::encode(ComputeGraph* graph) {
 
   bind_params_to_descriptor_set(params_, descriptor_set, idx);
 
-  uint8_t push_constants_data[128];
+  std::array<uint8_t, kMaxPushConstantSize> push_constants_data;
   uint32_t push_constants_offset = 0;
 
   for (const auto& push_constant : push_constants_) {
-    push_constants_offset +=
-        push_constant.write(push_constants_data, push_constants_offset, 128);
+    push_constants_offset += push_constant.write(
+        push_constants_data.data(),
+        push_constants_offset,
+        kMaxPushConstantSize);
   }
   context->register_shader_dispatch(
       descriptor_set,
       pipeline_barrier,
       shader_,
       global_workgroup_size_,
-      push_constants_data,
+      push_constants_data.data(),
       push_constants_offset);
 
   context->report_shader_dispatch_end();

backends/vulkan/runtime/graph/ops/DispatchNode.h

@@ -18,6 +18,7 @@ namespace vkcompute {
 
 class ComputeGraph;
 
+constexpr uint32_t kMaxPushConstantSize = 128;
 /*
  * Represents a push constant data entry
  * Which is either shared pointer to a tensor's uniform data with an attribute