[Issue]: Add upload validation for Start & End Date fields

[ClaireValdivia]

Why is this issue important?

In early 2024, treasury added two conditional fields for all projects: Project_Start_Date__c and Project_End_Date__c - these are conditional fields that are required based on the value of Completion_Status__c

Partners have noticed that staff users often forget to complete these fields, so would like if validation errors could run if they don't have a value input and they meet the conditions for the field to be required.

Current State

There is no validation error if project start date & project end date are blank when they meet the conditions to be required.

Expected State

Start Date

• Project_Start_Date__c is required if Completion_Status__c is "Completed less than 50%", "Completed 50% or more" or "Completed". If a project has one of these statuses but a value is not submitted for Project_Start_Date__c, an error will generate for upload validation with the message: "Value is required for Project_Start_Date__c" and the relevant workbook tab, row, and column are listed with the location of the Start date field.
• If Completion_Status__c for a project is "Not Started" or "Cancelled", and Start date is blank, no error will generate during validation.
• If a project's Completion_Status__c is "Completed less than 50%", "Completed 50% or more" or "Completed" and a value is entered for Project_Start_Date__c, no error will generate during validation

End Date

• Project_End_Date__c is required if Completion_Status__c is "Completed". If Completion_Status__c is "Completed" but there is no value entered for the field Project_End_Date__c, an error will generate during upload validation with the message: "Value is required for Project_End_Date__c" and the relevant workbook tab, row, and column will be listed with the location of the End date field.
• If Completion_Status__c is "Not Started", "Completed less than 50%", "Completed 50% or more", or "Cancelled", and End date is blank, no error will generate
• If Completion_Status__c is "Completed" and Project_End_Date__c has a value entered, no error will generate during upload validation.

Implementation Plan

The following functions need to be added...

Relevant Code Snippets