Feature Request Camera target alpha channel support

Hi there.

I noticed that the HDR camera target format in URP is RenderTextureFormat.RGB111110Float, which does not support an alpha channel. LDR rendering uses ARGB32 which has an alpha channel available (which by the way, does not get cleared properly by the camera: the alpha is always 1). Instead of having a checkbox for switching between the two, could we maybe get an enum with LDR, HDR, HDR (With Alpha), where the last one uses ARGBHalf? It sucks that you have to offer up HDR rendering if you want alpha channel support.
Rendering to the alpha channel can be quite powerful for certain effects, such as lens flares (depth buffer isn't enough if you have lots of transparent geometry, or if you don't want to render depth) or custom camera composite effects.

Cheers!