major: set default schema for kysely migration tables

[austin-hall-skylight]

PULL REQUEST

Summary

Sets default schema for Kysley migration tables to match the schema of the other tables we are creating instead of writing them to the database default. Removes schema creation from init migration.

Related Issue

Fixes #1102

Acceptance Criteria

• Create a script (or scripts, this needs to work for both DB types) for upgrading users to run manually which copies the data from both of their default schema migration tables into a new version under the ecr_viewer schema.
• Coordinate with devOps to create the ecr_viewer schema during the infrastructure setup stage
• Update migrations to no longer create schema, and change the initial migration to throw if the ecr_viewer schema does NOT exist
• Update the getMigrator function in migrate.ts to specify that migrationTableName and migrationLockTableName fall under the ecr_viewer schema
• Write clear documentation for STLTs making this upgrade to follow

Additional Information

Anything else the review team should know?

Checklist

• If this code affects the other scrum team, have they been notified? (In Slack, as reviewers, etc.)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 80.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.53%. Comparing base (428fd96) to head (93f0340).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...grate-db/migrations/core/19700101000000_initial.ts	62.50%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1141      +/-   ##
==========================================
+ Coverage   86.03%   90.53%   +4.49%     
==========================================
  Files         253      174      -79     
  Lines       11248     6505    -4743     
  Branches     1189     1198       +9     
==========================================
- Hits         9677     5889    -3788     
+ Misses       1564      609     -955     
  Partials        7        7              

Flag	Coverage Δ
ecr-viewer	91.72% <66.66%> (-0.05%)	⬇️
ingestion	?
message-parser	?
orchestration	85.12% <ø> (ø)
trigger-code-reference	?

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[austin-hall-skylight]

Waiting for this PR to be merged and released before this can be completed.