Refactor: /src/screens/UserPortal/LeaveOrganization/LeaveOrganization.test.tsx from jest to vitest

[raggettii]

Is your feature request related to a problem? Please describe.
The 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.

Describe the solution you'd like
Refactor the file from jest to vitest

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Approach to be followed (optional)
A clear and concise description of approach to be followed.

Additional context

1. Refer to the merged PR for the base Vitest configuration: https://github.com/PalisadoesFoundation/talawa-admin/pull/2457/files#diff-9a5a35cf8d7f02b2bba90905714b762560579c4789e9eb4cebb4607980aa3d93
2. Vitest reference site: 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 this to me

[shivasankaran18]

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

[swastikCommits]

can I work on this issue?