Remove "RUS: AdGuard Russian" from stock filter list

As per feedback from maintainers, AdGuard Russian
and RU AdList are incompatible and web site breakage
can occur when both are used together.

Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/749

assets/assets.json

@@ -559,16 +559,6 @@
 		"supportURL": "https://forums.lanik.us/viewforum.php?f=102",
 		"instructionURL": "https://forums.lanik.us/viewtopic.php?f=102&t=22512"
 	},
-	"RUS-2": {
-		"content": "filters",
-		"group": "regions",
-		"off": true,
-		"title": "RUS: AdGuard Russian",
-		"lang": "be kk ru uk uz",
-		"contentURL": "https://filters.adtidy.org/extension/ublock/filters/1.txt",
-		"supportURL": "https://forum.adguard.com/forumdisplay.php?69-%D0%A4%D0%B8%D0%BB%D1%8C%D1%82%D1%80%D1%8B-Adguard",
-		"instructionURL": "https://kb.adguard.com/ru/general/adguard-ad-filters#russian"
-	},
 	"spa-0": {
 		"content": "filters",
 		"group": "regions",