Fix cross-platform line ending issue in multiplicity tests

The verbatim string literals in these tests contained CRLF from the
source file, but on Linux CI the implementation outputs LF via
Environment.NewLine. Added .Replace("\r\n", "\n") to expected strings
to normalize line endings on both platforms.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: robertmclaws

src/Microsoft.Data.Entity.Tests.Design/CodeGeneration/Configuration/NavigationProperty/MultiplicityConfigurationTests.cs

@@ -37,7 +37,7 @@ public void GetMethodChain_returns_chan_when_many_to_many()
             configuration.GetMethodChain(code).Replace("\r\n", "\n").Should().Be(
                 @".Entity<Entity1>()
                 .HasMany(e => e.Entity2s)
-                .WithMany(e => e.Entity1s)");
+                .WithMany(e => e.Entity1s)".Replace("\r\n", "\n"));
         }
 
         [TestMethod]
@@ -62,7 +62,7 @@ public void GetMethodChain_returns_chan_when_many_to_required()
             configuration.GetMethodChain(code).Replace("\r\n", "\n").Should().Be(
                 @".Entity<Entity1>()
                 .HasMany(e => e.Entity2s)
-                .WithRequired(e => e.Entity1)");
+                .WithRequired(e => e.Entity1)".Replace("\r\n", "\n"));
         }
 
         [TestMethod]
@@ -87,7 +87,7 @@ public void GetMethodChain_returns_chan_when_many_to_optional()
             configuration.GetMethodChain(code).Replace("\r\n", "\n").Should().Be(
                 @".Entity<Entity1>()
                 .HasMany(e => e.Entity2s)
-                .WithOptional(e => e.Entity1)");
+                .WithOptional(e => e.Entity1)".Replace("\r\n", "\n"));
         }
 
         [TestMethod]
@@ -112,7 +112,7 @@ public void GetMethodChain_returns_chan_when_required_to_many()
             configuration.GetMethodChain(code).Replace("\r\n", "\n").Should().Be(
                 @".Entity<Entity1>()
                 .HasRequired(e => e.Entity2)
-                .WithMany(e => e.Entity1s)");
+                .WithMany(e => e.Entity1s)".Replace("\r\n", "\n"));
         }
 
         [TestMethod]
@@ -137,7 +137,7 @@ public void GetMethodChain_returns_chan_when_required_to_optional()
             configuration.GetMethodChain(code).Replace("\r\n", "\n").Should().Be(
                 @".Entity<Entity1>()
                 .HasRequired(e => e.Entity2)
-                .WithOptional(e => e.Entity1)");
+                .WithOptional(e => e.Entity1)".Replace("\r\n", "\n"));
         }
 
         [TestMethod]
@@ -162,7 +162,7 @@ public void GetMethodChain_returns_chan_when_optional_to_many()
             configuration.GetMethodChain(code).Replace("\r\n", "\n").Should().Be(
                 @".Entity<Entity1>()
                 .HasOptional(e => e.Entity2)
-                .WithMany(e => e.Entity1s)");
+                .WithMany(e => e.Entity1s)".Replace("\r\n", "\n"));
         }
 
         [TestMethod]
@@ -187,7 +187,7 @@ public void GetMethodChain_returns_chan_when_optional_to_required()
             configuration.GetMethodChain(code).Replace("\r\n", "\n").Should().Be(
                 @".Entity<Entity1>()
                 .HasOptional(e => e.Entity2)
-                .WithRequired(e => e.Entity1)");
+                .WithRequired(e => e.Entity1)".Replace("\r\n", "\n"));
         }
 
         private class Entity1