Fix interview response validation for expired interviews

[nishi240931]

Summary

Fixed the issue where CustomInterviewResponse inherited create-time validation from CustomInterviewCreate, causing validation errors when retrieving interviews whose dates had already passed.

Changes

• Added CustomInterviewBase to hold shared interview fields
• Kept future-date validation inside CustomInterviewCreate
• Updated CustomInterviewResponse to inherit from CustomInterviewBase

Result

Organizations can now fetch interview details even after the interview start time, end time, or submission deadline has passed.

[RITVIKKAMASETTY]

@nishi240931 what's the error can you share the screenshot and explain this more clearly

[nishi240931]

@RITVIKKAMASETTY The issue was that CustomInterviewResponse previously inherited from CustomInterviewCreate.

CustomInterviewCreate contains the validate_times_and_scores() validator, which enforces that start_time, end_time, and submission_deadline must be in the future.

Because the response schema inherited from the create schema, the same validation was triggered when fetching existing interviews. As a result, once an interview started or its submission deadline passed, retrieving interview details could fail with errors such as start_time must be in the future.

To fix this, I introduced CustomInterviewBase for shared fields, kept the validation only in CustomInterviewCreate, and updated CustomInterviewResponse to inherit from the base schema instead.