fix(eslint-plugin): [no-magic-numbers] fix invalid schema merging (#4517)

Author: ddubrava

packages/eslint-plugin/src/rules/no-magic-numbers.ts

@@ -9,7 +9,10 @@ type MessageIds = util.InferMessageIdsTypeFromRule<typeof baseRule>;
 
 // Extend base schema with additional property to ignore TS numeric literal types
 const schema = util.deepMerge(
- { ...baseRule.meta.schema },
+ // eslint-disable-next-line @typescript-eslint/no-unsafe-argument -- https://github.com/microsoft/TypeScript/issues/17002
+ Array.isArray(baseRule.meta.schema)
+ ? baseRule.meta.schema[0]
+ : baseRule.meta.schema,
  {
  properties: {
  ignoreNumericLiteralTypes: {