create manifest error when use http registry 80 port

Description

Steps to reproduce the issue:

1. config /etc/docker/daemon.json and add registry.com to insecure-registries
2. use http registry and registry use 80 port(eg: registry.com)
3. docker login registry.com -u xxx -p xxx
4. docker manifest create registry.com/a:1.0 registry.com/a-arm:1.0 --insecure --amend

if use below steps, will success

1. config `/etc/docker/daemon.json` and  add `registry.com:80` to `insecure-registries`
2. use http registry and registry use 80 port(eg: registry.com)
3. docker login registry.com:80 -u xxx -p xxx
4. docker manifest create registry.com:80/a:1.0  registry.com:80/a-arm:1.0 --insecure --amend

Describe the results you received:

Get "https://registry.com/v2/" dial tcp {ip}:443 connection refused

Describe the results you expected:

i expected manifest create success

Additional information you deem important (e.g. issue happens only occasionally):

Output of docker version:

Client:
  version: 20.10.8
  API version: 1.41
  Go version: go1.16.6
  OS/arch: linux/arm64
  Experimental: true
  Context: default
Server:
  Engines:
    Version: 20.10.8
    Api version: 1.41(minimum version 1.12)
    Go version: go1.16.6
    OS/arch: linux/arm64
    Experimental: true
  Containerd:
    Version: v1.4.9
  runc:
   Version: 1.0.1
  docker-init:
    Version: 0.19.0  

Output of docker info:

I cannot paste on the intranet

Additional environment details (AWS, VirtualBox, physical, etc.):

VMware, arm64

Start with the docker manifest create command and trace how registry references from the reproduction are handled alongside /etc/docker/daemon.json insecure registries. Reproduce the HTTP registry case with an omitted :80, compare it with the working explicit-port case, and verify that manifest creation succeeds without forcing HTTPS on port 443.