Move emptiness check to hasValidPort

src/bun.js/webcore/response.zig

@@ -2241,7 +2241,7 @@ pub const Fetch = struct {
             return globalObject.ERR_INVALID_ARG_TYPE(fetch_error_blank_url, .{}).throw();
         }
 
-        if (url.port.len > 0 and !url.hasValidPort()) {
+        if (!url.hasValidPort()) {
             bun.default_allocator.free(url.href);
             return globalObject.throwInvalidArguments("Invalid port", .{});
         }

src/url.zig

@@ -140,7 +140,7 @@ pub const URL = struct {
     }
 
     pub fn hasValidPort(this: *const URL) bool {
-        return (this.getPort() orelse 0) > 0;
+        return this.port.len == 0 or (this.getPort() orelse 0) > 0;
     }
 
     pub fn isEmpty(this: *const URL) bool {