Add global quality to the Anycubic i3 Mega

Fixes #4876.

resources/quality/anycubic_i3_mega/anycubic_i3_mega_draft.inst.cfg

@@ -8,6 +8,7 @@ setting_version = 5
 type = quality
 quality_type = draft
 weight = 0
+global_quality = True
 
 [values]
 acceleration_enabled = True

resources/quality/anycubic_i3_mega/anycubic_i3_mega_high.inst.cfg

@@ -8,6 +8,7 @@ setting_version = 5
 type = quality
 quality_type = high
 weight = 2
+global_quality = True
 
 [values]
 acceleration_enabled = True

resources/quality/anycubic_i3_mega/anycubic_i3_mega_normal.inst.cfg

@@ -8,6 +8,7 @@ setting_version = 5
 type = quality
 quality_type = normal
 weight = 1
+global_quality = True
 
 [values]
 acceleration_enabled = True