feat(dashboards): Implements syncing prebuilt dashboards to backend

[edwardgou-sentry]

Lazily creates prebuilt dashboards on fetch if they do not already exist in the database. Stored prebuilt dashboards are mostly empty except for a prebuilt_id that will be used in the frontend to determine the type of content to display in the ui.
Model changes:

• Adds prebuilt_id as a new column in the dashboards model + a constraint
• Updates created_by_id to be nullable, since prebuilt dashboards are not created by a user

https://linear.app/getsentry/document/how-will-we-store-static-dashboards-0d85ebe8c8ae

[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/0998_add_prebuilt_id_to_dashboards.py

for 0998_add_prebuilt_id_to_dashboards in sentry

--
-- Add field prebuilt_id to dashboard
--
ALTER TABLE "sentry_dashboard" ADD COLUMN "prebuilt_id" integer DEFAULT NULL NULL CHECK ("prebuilt_id" >= 0);
--
-- Alter field created_by_id on dashboard
--
ALTER TABLE "sentry_dashboard" ALTER COLUMN "created_by_id" DROP NOT NULL;
--
-- Create constraint sentry_dashboard_organization_prebuilt_id_uniq on model dashboard
--
CREATE UNIQUE INDEX CONCURRENTLY "sentry_dashboard_organization_prebuilt_id_uniq" ON "sentry_dashboard" ("organization_id", "prebuilt_id") WHERE "prebuilt_id" IS NOT NULL;
--
-- Create constraint sentry_dashboard_prebuilt_null_created_by on model dashboard
--
ALTER TABLE "sentry_dashboard" ADD CONSTRAINT "sentry_dashboard_prebuilt_null_created_by" CHECK (("prebuilt_id" IS NULL OR "created_by_id" IS NULL)) NOT VALID;
ALTER TABLE "sentry_dashboard" VALIDATE CONSTRAINT "sentry_dashboard_prebuilt_null_created_by";

[codecov]

Codecov Report

❌ Patch coverage is 89.18919% with 4 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...ry/dashboards/endpoints/organization_dashboards.py	86.20%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #101968      +/-   ##
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+ Coverage   73.25%    80.96%   +7.71%     
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  Files        8726      8729       +3     
  Lines      388171    388444     +273     
  Branches    24628     24627       -1     
===========================================
+ Hits       284347    314519   +30172     
+ Misses     103464     73565   -29899     
  Partials      360       360              

[edwardgou-sentry]

Theres an awkward thing where we already have an existing concept of prebuilt dashboards ie the default-overview dashboard, but we should plan for it to be deprecated and deleted.

[markstory]

If you're excluding none in the conditions, I don't think this filter condition will be hit.

[edwardgou-sentry]

So I had to add this here because mypy would still interpret id as int | None despite the filter condition.
I think this should be fine? Alternatively should we just add a type ignore? Let me know what you think!

[markstory]

ah ok. Sacrifices must be made to the mypy gods 🔥

[markstory]

What happens when a user attempts to update a pre-built dashboard, or delete one?

[edwardgou-sentry]

We'll be locking down these dashboards so they can't be edited or deleted by users. Will be adding this in a follow up PR!

[markstory]

Looks good to me.