Refactor: src/utils/convertToBase64.test.ts from Jest to Vitest

[palisadoes]

Is your feature request related to a problem? Please describe.
This file is currently tested using Jest. As part of our migration to Vitest, we need to refactor this file's test cases to align with Vitest's syntax and features.

Acceptance Criteria

1. Replace Jest-specific functions and mocks with Vitest equivalents
2. Rename the test file from having a .test.* suffix to a .spec.* suffix
3. Ensure all tests in the file pass after migration using npm run test:vitest
4. Maintain the test coverage for the file as 100% after migration
5. Upload a video or photo for this specific file coverage is 100% in the PR description

Additional context

• Refer to the merged PR for the base Vitest configuration:
  https://github.com/PalisadoesFoundation/talawa-admin/pull/2457/files#diff-9a5a35cf8d7f02b2bba90905714b762560579c4789e9eb4cebb4607980aa3d93
• Vitest documentation:
  https://vitest.dev/

Potential internship candidates

Please read this if you are planning to apply for a Palisadoes Foundation internship

• Student Internship Programs talawa#359

[raggettii]

@palisadoes, please assign it to me

[palisadoes]

@palisadoes, please assign it to me

Our policy is to assign no more than two issues to each contributor across all repositories. This way everyone gets a chance to participate in the projects. We sometimes give exceptions for more urgent cases and sometimes we lose track, but the policy stands. You have reached your limit, please wait until your existing issues are closed before requesting more issues. You could unassign yourself from one of the other issues too.

[AceHunterr]

@palisadoes please assign this issue to me

[Dhiren-Mhatre]

@palisadoes I would like to request assignment for this issue. Here's how I plan to handle the migration from Jest to Vitest:

1. I will first analyze the existing convertToBase64.test.ts file to identify all Jest-specific syntax and functionality that needs to be updated.

2. My migration approach will include:

   • Renaming the file to convertToBase64.spec.ts
   • Converting Jest test syntax to Vitest equivalents
   • Ensuring all mocks and test utilities are updated to use Vitest
   • Running the test suite to verify all tests pass
   • Verifying 100% test coverage is maintained

3. I will follow the existing Vitest configuration from PR feat!: Migrate Testing Framework from Jest to Vitest #2457 and refer to the official Vitest documentation for best practices.

4. I will include test coverage screenshots in my PR to demonstrate maintained coverage levels.

I'm familiar with both Jest and Vitest testing frameworks and am confident I can complete this migration while maintaining test quality and coverage.