Revert "Use PRAGMA defer_foreign_keys instead of PRAGMA foreign_keys when migrating"

[cincuranet]

Reverts #35873.
Fixes #37598.

[Copilot]

Pull request overview

Reverts the SQLite migrations behavior introduced in #35873 by switching back from PRAGMA defer_foreign_keys to toggling PRAGMA foreign_keys during table rebuild migrations, addressing the data-loss scenario described in #37598.

Changes:

• Update SQLite migrations SQL generation to emit PRAGMA foreign_keys = 0/1 with transaction suppression around rebuild drop/rename steps.
• Update SQLite migrations SQL generator unit tests to match the new PRAGMA output.
• Update functional migration SQL assertions to include the disable/enable foreign keys PRAGMAs.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/EFCore.Sqlite.Core/Migrations/SqliteMigrationsSqlGenerator.cs	Replaces defer_foreign_keys with transaction-suppressed foreign_keys off/on operations around rebuild drop/rename.
test/EFCore.Sqlite.FunctionalTests/Migrations/SqliteMigrationsSqlGeneratorTest.cs	Updates expected SQL strings to assert PRAGMA foreign_keys = 0 before drop/rename and = 1 after.
test/EFCore.Sqlite.FunctionalTests/Migrations/MigrationsSqliteTest.cs	Updates functional test SQL command expectations to include the new PRAGMA off/on commands.