chore: add unit test coverage for untested code paths in `@asgardeo/browser`

首先检查 @asgardeo/browser 包的最新覆盖率，并使用 Vitest 运行其现有的单元测试套件，以确定未测试的行和分支。选择一个特定的函数、方法或组件，然后为正常、边界和无效输入添加测试；当测试通过且所选路径已被覆盖时，即表示完成。

Current Limitation

Some code paths and edge cases in @asgardeo/browser are not covered by unit tests, leading to reduced confidence in code changes, potential bugs, and lower test coverage.

• Reduced confidence in code changes and refactoring
• Potential undetected bugs in less common scenarios
• Lower overall test coverage metrics
• Increased manual testing effort
• Difficulty in maintaining code quality over time

Without adequate unit tests, the codebase may contain:

• Functions or methods that are not validated for all input variations
• Edge cases that may break silently
• Logic errors that are only caught in integration or production environments

Suggested Improvement

Identify and add unit tests for untested code paths and edge cases in @asgardeo/browser. Improve test coverage and reliability.

Implementation Plan

1. Review the latest code coverage to identify untested lines/branches.
2. Select a function, method, or component that lacks test coverage.
3. Write a new unit test that:
   • Covers normal, boundary, and invalid input cases
   • Asserts correct output and expected error handling
4. Run the test suite to confirm the new test is effective and passes.
5. Update documentation or test coverage badges as necessary.

References:

• https://vitest.dev/
• Improving test coverage

Please select the package issue is related to

@asgardeo/browser

Version

Current

Reporter Checklist

• I have searched the existing issues and this is not a duplicate.
• I have provided all the necessary information.
• I have verified the improvement is not available in the latest version of the package.