Blender Git Loki

Fix T82824: Draw sensor size with correct alpha

Previously the option in the camera's //Object Data Properties > Viewport Display
> Sensor// would not display the sensor in camera view. This seemed to be caused
by the theme color `TH_VIEW_OVERLAY` having zero set for the alpha channel and
alpha blending being active, resulting in no visible output. Hence
`immUniformThemeColorShade(TH_VIEW_OVERLAY, 100);` is replaced with
`immUniformThemeColorShadeAlpha(TH_VIEW_OVERLAY, 100, 255);`.

Reviewed By: mano-wii

Differential Revision: https://developer.blender.org/D11075