Refactor: src/screens/EventManagement from Jest to Vitest

[VanshikaSabharwal]

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. Ensure all tests in src/screens/EventManagement pass after migration using npm run test:vitest
3. Maintain the test coverage for the file as 100% after migration
4. 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

[Adhish1612Acharya]

Hello @palisadoes ,

I would like to work on this issue. Could you please assign it to me?

[shivasankaran18]

@Adhish1612Acharya are you still working on this..?..can I work on it

[palisadoes]

Unassigning. Inactive and no PR

[palisadoes]

1. @prathmesh703 You should work on this issue too
2. Ask to be assigned

[prathmesh703]

sure , @palisadoes you can assign this issue to me

[shivasankaran18]

can I work on this issue ..? @palisadoes @Cioppolo14

[prathmesh703]

@shivasankaran18 i have completed the work of this issue and is linked in PR which also resolves the other issue

[Cioppolo14]

@prathmesh703 If your still working on the issue, please do not unassign yourself.

[Cioppolo14]

@prathmesh703 I am going to reassign you this item, but please do not repeat this strategy.

[prathmesh703]

@Cioppolo14 sorry for this thing , actually i have made a PR(#3149) for this issue and for other issue(#3024) that's why i have unassigned myself from this issue and asked you to assign another issue.