Remove dup stylelint depdendencies in webapp/channels (#27499)

webapp/channels/package.json

@@ -93,7 +93,6 @@
     "smooth-scroll-into-view-if-needed": "1.1.33",
     "stream-browserify": "3.0.0",
     "styled-components": "5.3.6",
-    "stylelint": "13.13.1",
     "timezones.json": "1.6.1",
     "tinycolor2": "1.4.2",
     "turndown": "7.1.1",

webapp/package-lock.json

@@ -142,7 +142,6 @@
         "smooth-scroll-into-view-if-needed": "1.1.33",
         "stream-browserify": "3.0.0",
         "styled-components": "5.3.6",
-        "stylelint": "13.13.1",
         "timezones.json": "1.6.1",
         "tinycolor2": "1.4.2",
         "turndown": "7.1.1",