use logger.LogOnce to reduce printing disconnection logs (#15408)

fixes #15334

- re-use net/url parsed value for http.Request{}
- remove gosimple, structcheck and unusued due to https://github.com/golangci/golangci-lint/issues/2649
- unwrapErrs upto leafErr to ensure that we store exactly the correct errors

.golangci.yml

@@ -14,13 +14,9 @@ linters:
     - govet
     - revive
     - ineffassign
-    - gosimple
     - deadcode
-    - structcheck
     - gomodguard
     - gofmt
-    - unused
-    - structcheck
     - unconvert
     - varcheck
     - gocritic