Remove clamp function in contrast fragment shader.

* OpenGL automatically clamps the output colors to the [0, 1] interval.

PiperOrigin-RevId: 465071999
(cherry picked from commit 2347db5d)

libraries/effect/src/main/assets/shaders/fragment_shader_contrast_es2.glsl

@@ -26,8 +26,8 @@ void main() {
     vec4 inputColor = texture2D(uTexSampler, vTexSamplingCoord);
     vec4 inputColor = texture2D(uTexSampler, vTexSamplingCoord);
 
 
     gl_FragColor = vec4(
     gl_FragColor = vec4(
-        clamp(uContrastFactor * (inputColor.r - 0.5) + 0.5, 0.0, 1.0),
-        clamp(uContrastFactor * (inputColor.g - 0.5) + 0.5, 0.0, 1.0),
-        clamp(uContrastFactor * (inputColor.b - 0.5) + 0.5, 0.0, 1.0),
+        uContrastFactor * (inputColor.r - 0.5) + 0.5,
+        uContrastFactor * (inputColor.g - 0.5) + 0.5,
+        uContrastFactor * (inputColor.b - 0.5) + 0.5,
         inputColor.a);
         inputColor.a);
 }
 }