Fixed missing "global::" for attributes on builder

.editorconfig

@@ -16,4 +16,4 @@ indent_style = tab
 indent_style = tab
 
 [*.json]
-indent_style = tab
+indent_style = tab

src/Uno.CodeGen/ImmutableGenerator.cs

@@ -961,7 +961,7 @@ $@"public sealed class {symbolName}BuilderJsonConverterTo{symbolName}{genericArg
 						continue; // should be ignored
 					}
 
-					yield return $"[{attrResult}]{Environment.NewLine}";
+					yield return $"[global::{attrResult}]{Environment.NewLine}";
 				}
 			}