GameSettings: Set texture cache accuracy for Pokémon Channel

This game contains a special episode of the Pokémon anime as an FMV.
When playing it, if only a tiny part of the image has changed between
frames, Dolphin's texture hashing can fail to notice that anything
changed, or it can notice that the chroma changed but not the luma, or
vice versa.

512 samples reduces the problem but doesn't get rid of it entirely, but
with 2048 I'm unable to see the problem.

Data/Sys/GameSettings/GPA.ini

@@ -10,5 +10,9 @@
 # Add action replay cheats here.
 
 [Video_Hacks]
+# Required for Smeargle Paint
 EFBToTextureEnable = False
 
+[Video_Settings]
+# Avoid skipping frames in the anime (most noticeable in part 3)
+SafeTextureCacheColorSamples = 2048