"Scaffold" triggers for SQL Server

[roji]

HasTrigger with trigger name only, to make the SQL Server SaveChanges work out of the box.

Closes #28185

[roji]

Note that the annotation value here is HashSet<string>, which is different from what we do via the Fluent API (Dictionary<string, ITrigger>), because ITrigger needs to reference an IMutableEntityType which we don't have here. The translation from this to that happens in RelationalScaffoldingModelFactory.

[roji]

Scaffolding codegen needs to happen in CSharpDbContextGenerator and not in AnnotationCodeGenerator, since on the model snapshot side special code handles triggers in CSharpSnapshotGenerator. Should have done this after @bricelam's template work :(

[AndriySvyryd]

[ErikEJ]

LGTM - makes using previews a better experience.

[roji]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[roji]

Ready for review, unrelated Cosmos test failures due to flakiness (:angry:)

[ajcvickers]

Why are the Cosmos tests running on that build? Did we enable Cosmos there at some point and I forgot about it? @smitpatel?

[ajcvickers]

Also, it's interesting that it's new tests (Regex_IsMatch_MethodCall...) that are failing. Is there something different about how these tests work than the other tests? I.e. are we sure this is Cosmos flakiness and not something flaky in the new tests?

[roji]

Agree that it's strange! Though also not supposed to be related to this PR in any way...

[smitpatel]

Use ConditionalFact

efcore/test/EFCore.Cosmos.FunctionalTests/Query/NorthwindFunctionsQueryCosmosTest.cs

Lines 1316 to 1324 in bda79d4

	[Fact]
	public virtual void Regex_IsMatch_MethodCall_With_Unsupported_Option()
	=> Assert.Throws<InvalidOperationException>(() =>
	Fixture.CreateContext().Customers.Where(o => Regex.IsMatch(o.CustomerID, "^T", RegexOptions.RightToLeft)).ToList());
	[Fact]
	public virtual void Regex_IsMatch_MethodCall_With_Any_Unsupported_Option()
	=> Assert.Throws<InvalidOperationException>(() =>
	Fixture.CreateContext().Customers.Where(o => Regex.IsMatch(o.CustomerID, "^T", RegexOptions.IgnoreCase | RegexOptions.RightToLeft)).ToList());

[roji]

@smitpatel did that locally as part of #28139, PR out soon.