chore(sonar): second sweep — catch .Length, Is.Not.Empty, and newly-exposed Multiple groups (NUnit2046, NUnit2045)

Re-runs `dotnet format analyzers --diagnostics NUnit2046 NUnit2045` after
the Tier 2 Assert.Multiple wrap, which exposed:

- `Has.Length.EqualTo(n)` rewrites for `string[]`/array `.Length` checks
  (the first pass only knew about `.Count`).
- `Is.Not.Empty` rewrites for `Count, Is.GreaterThan(0)`.
- A handful of new NUnit2045 groups that became wrappable once the
  initial Multiple blocks settled the surrounding indentation.

Tests still 1180/1180 passing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/Strata.SqlTools.SqlBreakdown.Tests/ExpressionTests/DateFunctionTests.cs

@@ -27,7 +27,7 @@ public class DateFunctionTests : ExpressionTestsBase
                 {
                     var sql = (string)result;
                     Assert.That(sql, Is.Not.Null);
-                    Assert.That(sql.Length, Is.GreaterThan(0));
+                    Assert.That(sql, Is.Not.Empty);
                     Assert.That(sql, Is.EqualTo("DATE_TRUNC('month', DATEADD('month', 6, PES.DISCHARGE_DATE))"));
                     return true;
                 }

tests/Strata.SqlTools.SqlBreakdown.Tests/ExpressionTests/ExpressionFactoryFilterTests.cs

@@ -52,7 +52,7 @@ public class ExpressionFactoryFilterTests : ExpressionTestsBase
 
         // Assert
         Assert.That(result, Is.Not.Null);
-        Assert.That(result.Length, Is.GreaterThan(0));
+        Assert.That(result, Is.Not.Empty);
         Assert.That(result, Is.EqualTo(expectedSql));
     }
 }

tests/Strata.SqlTools.SqlBreakdown.Tests/ExpressionTests/GenericColumnExpressionTests.cs

@@ -65,9 +65,8 @@ public class GenericColumnExpressionTests : ExpressionTestsBase
                 Assertions = result =>
                 {
                     var results = (Dictionary<string, string>)result;
-                    Assert.That(results["priceCondition"], Does.Contain("Price"));
-                    Assert.That(results["priceCondition"], Does.Contain("100"));
-                    Assert.That(results["categoryCondition"], Does.Contain("Category"));
+                    Assert.That(results["priceCondition"], Does.Contain("Price")); Assert.Multiple(() => { Assert.That(results["priceCondition"], Does.Contain("100"));
+                    Assert.That(results["categoryCondition"], Does.Contain("Category")); });
                     Assert.That(results["categoryCondition"], Does.Contain("Electronics"));
                     return true;
                 }