Emit a table-valued function without LATERAL. Fix #1277

VisitCrossApply and VisitOuterApply put LATERAL in front of whatever EF Core
hands them. In Firebird's grammar LATERAL is a prefix on a derived table only:

    <table-primary> ::=
        <table-or-query-name> [[AS] correlation-name]
      | [LATERAL] <derived-table> [<correlation-or-recognition>]
      | <parenthesized-joined-table>

    <table-or-query-name> ::=
        table-name | query-name | [package-name.]procedure-name [(<procedure-args>)]

A selectable procedure is the other alternative, and its arguments may already
reference streams declared earlier in the FROM clause. So a correlated queryable
function needs no LATERAL - and cannot have one, which is why it did not parse.

    JOIN LATERAL "GetCustomerOrderCountByYear"("c"."Id") AS "g" ON TRUE
    -- Dynamic SQL Error, SQL error code = -104, Token unknown

    JOIN "GetCustomerOrderCountByYear"("c"."Id") AS "g" ON TRUE
    -- works, on Firebird 3 as well

The two visitors now share one GenerateApplySource, which emits the call as it
is emitted anywhere else and keeps LATERAL for the sources that need it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: azabluda

src/FirebirdSql.EntityFrameworkCore.Firebird/Query/Internal/FbQuerySqlGenerator.cs

@@ -285,24 +285,8 @@ protected override void GenerateOrderings(SelectExpression selectExpression)
 	// Copyright (c) 2002-2021, Npgsql
 	protected override Expression VisitCrossApply(CrossApplyExpression crossApplyExpression)
 	{
-		Sql.Append("JOIN LATERAL ");
-
-		if (crossApplyExpression.Table is TableExpression table)
-		{
-			// Firebird doesn't support LATERAL JOIN over table, and it doesn't really make sense to do it - but EF Core
-			// will sometimes generate that.
-			Sql
-				.Append("(SELECT * FROM ")
-				.Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(table.Name, table.Schema))
-				.Append(")")
-				.Append(AliasSeparator)
-				.Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(table.Alias));
-		}
-		else
-		{
-			Visit(crossApplyExpression.Table);
-		}
-
+		Sql.Append("JOIN ");
+		GenerateApplySource(crossApplyExpression.Table);
 		Sql.Append(" ON TRUE");
 		return crossApplyExpression;
 	}
@@ -312,26 +296,38 @@ protected override Expression VisitCrossApply(CrossApplyExpression crossApplyExp
 	// Copyright (c) 2002-2021, Npgsql
 	protected override Expression VisitOuterApply(OuterApplyExpression outerApplyExpression)
 	{
-		Sql.Append("LEFT JOIN LATERAL ");
+		Sql.Append("LEFT JOIN ");
+		GenerateApplySource(outerApplyExpression.Table);
+		Sql.Append(" ON TRUE");
+		return outerApplyExpression;
+	}
 
-		if (outerApplyExpression.Table is TableExpression table)
+	// LATERAL is only allowed in front of a derived table, so anything that is not one has to
+	// become one - except a selectable procedure, which is implicitly lateral already.
+	void GenerateApplySource(TableExpressionBase source)
+	{
+		if (source is TableValuedFunctionExpression function)
+		{
+			// A selectable procedure takes its arguments from streams earlier in the FROM clause
+			// without LATERAL, so the call is emitted as it is anywhere else.
+			Visit(function);
+		}
+		else if (source is TableExpression table)
 		{
 			// Firebird doesn't support LATERAL JOIN over table, and it doesn't really make sense to do it - but EF Core
 			// will sometimes generate that.
 			Sql
-				.Append("(SELECT * FROM ")
+				.Append("LATERAL (SELECT * FROM ")
 				.Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(table.Name, table.Schema))
 				.Append(")")
 				.Append(AliasSeparator)
 				.Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(table.Alias));
 		}
 		else
 		{
-			Visit(outerApplyExpression.Table);
+			Sql.Append("LATERAL ");
+			Visit(source);
 		}
-
-		Sql.Append(" ON TRUE");
-		return outerApplyExpression;
 	}
 
 	protected override void GeneratePseudoFromClause()