fix(goctl): multi imports the api cause redeclared error in types.go (#3988)

Co-authored-by: Kevin Wan <wanjunfeng@gmail.com>

tools/goctl/pkg/parser/api/parser/api.go

@@ -32,11 +32,8 @@ type API struct {
 func convert2API(a *ast.AST, importSet map[string]lang.PlaceholderType, is *importstack.ImportStack) (*API, error) {
 	var api = new(API)
 	api.importManager = is
-	api.importSet = make(map[string]lang.PlaceholderType)
+	api.importSet = importSet
 	api.Filename = a.Filename
-	for k, v := range importSet {
-		api.importSet[k] = v
-	}
 	one := a.Stmts[0]
 	syntax, ok := one.(*ast.SyntaxStmt)
 	if !ok {