Trim the mapping store type base name (#30593)

Fixes #30592

Author: roji

src/EFCore.Relational/Storage/RelationalTypeMapping.cs

@@ -298,7 +298,7 @@ static string GetBaseName(string storeType)
             var openParen = storeType.IndexOf("(", StringComparison.Ordinal);
             if (openParen >= 0)
             {
-                storeType = storeType[..openParen];
+                storeType = storeType[..openParen].TrimEnd();
             }
 
             return storeType;

test/EFCore.Relational.Tests/Storage/RelationalTypeMapperTest.cs

@@ -222,6 +222,21 @@ public void Does_type_mapping_from_decimal_type_with_configuration()
         Assert.False(mapping.IsFixedLength);
     }
 
+    [ConditionalFact]
+    public void StoreTypeNameBase_is_trimmed()
+    {
+        var mapping = GetTypeMapping(
+            typeof(string),
+            storeTypeName: "ansi_string_fixed (666)",
+            useConfiguration: true);
+
+        Assert.Equal("ansi_string_fixed (666)", mapping.StoreType);
+        Assert.Equal("ansi_string_fixed", mapping.StoreTypeNameBase);
+        Assert.Equal(666, mapping.Size);
+        Assert.False(mapping.IsUnicode);
+        Assert.False(mapping.IsFixedLength);
+    }
+
     protected override IRelationalTypeMappingSource CreateRelationalTypeMappingSource()
         => new TestRelationalTypeMappingSource(
             TestServiceFactory.Instance.Create<TypeMappingSourceDependencies>(),