Expand `String.prototype.chars` goody test to consider strings with emojis

This task is to update [`workspaces/adventure-pack/goodies/typescript/String.prototype.chars/index.test.ts`](../tree/main/workspaces/adventure-pack/goodies/typescript/String.prototype.chars/index.test.ts) to consider a wider range of strings. In particular, it would be nice to confirm that emojis, or other strings containing Unicode characters, are correctly handled.

从 workspaces/adventure-pack/goodies/typescript/String.prototype.chars/index.test.ts 开始，检查其中现有的字符串用例。添加涵盖表情符号和其他包含 Unicode 的字符串的用例，然后运行该文件的测试；完成的标准是扩展后的用例通过，并确认处理正确。

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