Move appearance variant to systemlink list (#142)

Minor follow-up to #141
to move `appearanceVariant` to the correct list.
The `sl-split-button` uses a different API from nimble currently so has
a different name for the localize ignore list.

`@Input('appearance-variant') public set appearanceVariant` in nimble vs
`@Input() public appearanceVariant` for sl-split-button. Note the
difference in the `@Input` decorator configuration.

change/@ni-eslint-config-angular-5b9c7b9d-f3dc-4cd2-ae70-26717d051203.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Move appearanceVariant to systemlink list",
+  "packageName": "@ni/eslint-config-angular",
+  "email": "rajsite@users.noreply.github.com",
+  "dependentChangeType": "patch"
+}

packages/eslint-config-angular/template/options.js

@@ -16,7 +16,6 @@ const ignoreAttributeSets = {
         'activeid',
         'appearance',
         'appearance-variant',
-        'appearanceVariant',
         'autocomplete',
         'column-id',
         'field-name',
@@ -58,6 +57,9 @@ const ignoreAttributeSets = {
         'loadColumnStateBehavior',
         'parentDataField',
 
+        // sl-split-button
+        'appearanceVariant',
+
         // sl-query-builder
         'dropdownWidth',
     ],