perf: LSDV-4695: Add Project relation to Prediction model to improve overall performance

[dredivaris]

PR fulfills these requirements

• Commit message(s) and PR title follows the format [fix|feat|ci|chore|doc]: TICKET-ID: Short description of change made ex. fix: DEV-XXXX: Removed inconsistent code usage causing intermittent errors
• Tests for the changes have been added/updated (for bug fixes/features)
• Docs have been added/updated (for bug fixes/features)
• Best efforts were made to ensure docs/code are concise and coherent (checked for spelling/grammatical errors, commented out code, debug logs etc.)
• Self-reviewed and ran all changes on a local instance (for bug fixes/features)

Change has impacts in these area(s)

(check all that apply)

• Product design
• Backend (Database)
• Backend (API)
• Frontend

Describe the reason for change

Prediction performance in general has not been optimal due to the necessity of querying through the task model whenever needing to filter on project (Prediction -> Task -> Project).

What does this fix?

This PR is the first of a set of 2 PRs. This PR adds migrations to add the a project foreign key field to Prediction as well as a data migration to populate the new field with the correct project for existing Predictions. I've also added changes across the code on Prediction saves / bulk saves etc to ensure any new Predictions added after the migration will store the project properly.

Once the first PR is live, the second PR will introduce changes to queries which use the new project relation rather than querying through task -> project.

The PRs were separated in this way because until all Predictions have been updated with the new project fk, the queries could not be optimized to use the fk.

What feature flags were used to cover this change?

None - and this is by design. I've introduced code changes here on all Prediction save's/bulk saves to save project_id on create. This is necessary because the next PR will introduce query updates that depend on this Prediction.project_id linkage and if its missing on any Predictions, the query will break. I'll use a feature flag on the following PR to test the query changes however.

Does this PR introduce a breaking change?

(check only one)

• Yes, and covered entirely by feature flag(s)
• Yes, and covered partially by feature flag(s)
• No
• Not sure (briefly explain the situation below)

What level of testing was included in the change?

(check all that apply)

• e2e
• integration
• unit

Which logical domain(s) does this change affect?

Predictions

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[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.01% ⚠️

Comparison is base (b6b1705) 75.85% compared to head (89060fd) 75.85%.
Report is 15 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4629      +/-   ##
===========================================
- Coverage    75.85%   75.85%   -0.01%     
===========================================
  Files          157      157              
  Lines        12487    12499      +12     
===========================================
+ Hits          9472     9481       +9     
- Misses        3015     3018       +3     

see 6 files with indirect coverage changes

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[sentry-io]

Suspect Issues

This pull request was deployed and Sentry observed the following issues:

• ‼️ ImportError: cannot import name 'fill_predictions_project' from 'tasks.functions' (/Users/ylim/code/roblox/hum... tasks.migrations.0042_auto_20230810_2304 in <mo... View Issue
• ‼️ TypeError: fill_predictions_project() missing 1 required positional argument: 'migration_name' tasks.migrations.0042_auto_20230810_2304 in for... View Issue

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