Niagara - Particle stage "Dynamic Material Parameters" module fetches parameter names, but not parameter default values, from material used on renderer

Note: the behavior described below is consistent on all UE versions from 4.27 to mainline latest.

The built-in Niagara Module "Dynamic Material Parameters", which is available for all particle stage scripts, allows setting the "DynamicMaterialParameter#" particle parameter, which by default is bound to the "Dynamic Material #Binding" on renderers. A nice feature of this module is that, on its Details Panel inside the Niagara Editor, the parameters being set correctly use the display names chosen in the "Dynamic Parameter" material node within the renderer material.

However, although the "Dynamic Parameter" material node also allows the user to choose default values for its parameters, these default values are not used by the details panel of the "Dynamic Material Parameters" niagara module. Instead, float parameters always have their defaults at 0.0, for example.

1. Create a Niagara System from the "SingleLoopingParticle" template.
2. Edit the Niagara System:
2.1. On the details panel for the "Sprite Renderer" Module, find the Material property and click the "browse to asset" icon
3. On the content browser, make a copy of the "DefaultSpriteMaterial"
4. Edit the new material
4.1. Replace the "Particle Color" node with a "Dynamic Parameter" node, link its outputs appropriately.
4.2. On the details panel, set up some "Param Names" and the "Default Value"
4.3. Apply and save
5. Back on the Niagara Editor:
5.1. On the "Sprite Renderer" module, replace the material with the one created above.
5.2. On the "Particle Update" stage, add a new "Dynamic Material Parameters" module
5.3. On the details panel for "Dynamic Material Parameters", note how the parameter names were successfully imported, but the default value was not (all parameters have 0.0 as the default).