Enable GLSL for Mali (Lima) / PinePhone devices

Commit 88cf8355 changed the behaviour of Mali (Lima) / PinePhone devices by disabling GLSL
88cf8355 got backported in 5.27.1 and broke PinePhone devices (White rectangle on topright quarter of a black screen)

This patch restores the behaviour of 5.27.0

autotests/libkwineffects/data/glplatform/lima-mali400-desktop-3.0

@@ -6,7 +6,7 @@ ShadingLanguageVersion=1.30
 
 [Settings]
 LooseBinding=true
-GLSL=false
+GLSL=true
 TextureNPOT=true
 Mesa=true
 Lima=true

src/libkwineffects/kwinglplatform.cpp

@@ -1138,8 +1138,7 @@ void GLPlatform::detect(OpenGLPlatformInterface platformInterface)
 
     if (isLima()) {
         m_recommendedCompositor = OpenGLCompositing;
-        // GLSL works but causes dramatic FPS drop on this GPU
-        m_supportsGLSL = false;
+        m_supportsGLSL = true;
     }
 
     if (isVideoCore4()) {