Is that possible to Convert Normal Layer to Shape Layer in Script

Only by using tricks and if that tricks works well. Workaround is to select content of layer in your case then to convert to path and finally to fill path with solid color what should create Shape layer. You can then delete original pixel based layer. You can record action but ... Action will depend on number of layers and their order in the Layers panel. If you always have same situation like bottom most layer is always in question then you can solve problem by recording action, otherwise you may need script.

If you mean a raster image layer into a shape layer the answer is no.  Shape layer are fill layer the have a vector layer mask.  The Fill  Layer is either Empty, A Solid Color, A  Gradient or Pattern fill layer.    Raster image layer can be  Mask  with A Vector Layer  Mask, with a Normal Raster Layer Mask.   Its like a Shape layer the Image is still a raster image it not vectorized. It still a Raster layer the has been masked.   

In Templates Image  that are replaced  are normally made into Smart Object Layers where  the smart object layer's Object Transform is used to Position, Scale and Warp the image for its use in the mockup template. These Smart Object layer in mockup template can also have un-linked Layer mask that hide un-wanted image area in the template.   

 A  template may  have Shape layers that are user as clipping Mask where a image layer are clipped to the shape layers to confine the images to shapes  in  some location over the Canvas. 

Are you trying to convert normal pixel based layers into shape layers? If so, is each pixel based shape on its own layer or do layers contain multiple elements? Any chance you could post some screen shots?