chore: remove unused shader code for frame interpolation

- Removed fragment shader that blended previous and current frames with a 50% linear interpolation
- This shader was no longer required or used in the current pipeline
- Better Interpolation Method Used

src/video_core/host_shaders/vulkan_interpolation.frag

@@ -1,16 +0,0 @@
-#version 450
-
-layout (binding = 0) uniform sampler2D previous_frame;
-layout (binding = 1) uniform sampler2D current_frame;
-layout (binding = 2, rgba8) uniform writeonly image2D result_image;
-
-void main() {
-    vec2 uv = gl_FragCoord.xy / imageSize(result_image);
-    vec4 prev_color = texture(previous_frame, uv);
-    vec4 curr_color = texture(current_frame, uv);
-
-    // Simple linear interpolation (50% blend)
-    vec4 interpolated_color = mix(prev_color, curr_color, 0.5);
-
-    imageStore(result_image, ivec2(gl_FragCoord.xy), interpolated_color);
-}