Fix: Sliders in animeditors were getting drawn too far left

Sliders in for FCurves in the animation editors were leaving space for
one extra setting that they didn't need to be accounting for (and which
wasn't shown, as it isn't valid for FCurves).

source/blender/editors/animation/anim_channels_defines.c

@@ -952,6 +952,7 @@ static bool acf_fcurve_setting_valid(bAnimContext *ac, bAnimListElem *ale, eAnim
 		/* unsupported */
 		case ACHANNEL_SETTING_SOLO:   /* Solo Flag is only for NLA */
 		case ACHANNEL_SETTING_EXPAND: /* F-Curves are not containers */
+		case ACHANNEL_SETTING_PINNED: /* This is only for NLA Actions */
 			return false;
 		
 		/* conditionally available */