Update SupportTicketApi to EF 9.0

[AndriySvyryd]

Related to dotnet/aspire#5207

• Move the migrations to SupportTicketApi.MigrationService and use it as the startup project in tooling. See Move migrations to DatabaseMigrations.MigrationService dotnet/aspire-samples#331
• EnsureDatabaseAsync should be removed as now this is handled well by MigrateAsync
• MigrateAsync shouldn't be wrapped in a transaction and execution strategy. This is now done internally, and the explicit wrapping can be detrimental in some cases (for migration operations that can't be executed in a transaction).
• Seeding should be done using the new UseAsyncSeeding method on DbContextOptionsBuilder. See Upgrade EF to 9.0 dotnet/eShop#488 for additional suggestions.

Also, use WaitForResourceAsync(...) when available.