Unittests for widget post_detailed_page.dart

[palisadoes]

We will need unittests done for all methods, classes and functions found in this file.

Any widgets referenced in this file must also have unittests done

post_detailed_page.dart

This file can be found in the lib/widgets directory

Parent Issue:

• https://github.com/PalisadoesFoundation/talawa/issues/1125

PR Acceptance Criteria

• When complete this file must show 100% coverage when merged into the code base.
• The current code coverage for the file can be found here
• The PR will show a report for the code coverage for the file you have added. You can use that as a guide

[ArchitJain1201]

Can I work on this issue @palisadoes

[Ayush0Chaudhary]

@palisadoes @noman2002 please assign me this