Organization folder icons are using not the Jenkins url

### Version report

Jenkins and plugins versions report:

``` plain
Jenkins: 2.277.3
OS: Linux - 4.4.0-210-generic
---
matrix-auth:2.6.6
data-tables-api:1.10.23-3
blueocean-config:1.24.6
docker-commons:1.17
trilead-api:1.0.13
blueocean-autofavorite:1.2.4
blueocean-pipeline-scm-api:1.24.6
matrix-project:1.18
gitlab-branch-source:1.5.7
script-security:1.76
pipeline-stage-view:2.19
handlebars:3.0.8
apache-httpcomponents-client-4-api:4.5.13-1.0
blueocean-commons:1.24.6
jsch:0.1.55.2
github:1.33.1
jackson2-api:2.12.3
dependency-track:3.1.1
junit:1.49
momentjs:1.1.1
blueocean-rest-impl:1.24.6
msbuild:1.30
forensics-api:1.0.0
run-condition:1.5
credentials:2.3.18
gitlab-plugin:1.5.20
variant:1.4
view-job-filters:2.3
influxdb:3.0
build-timeout:1.20
pipeline-utility-steps:2.7.1
pipeline-model-definition:1.8.4
workflow-cps-global-lib:2.19
cobertura:1.16
checks-api:1.7.0
ldap:2.6
pubsub-light:1.13
blueocean-web:1.24.6
pipeline-stage-step:2.5
branch-api:2.6.3
dashboard-view:2.15
jquery3-api:3.6.0-1
blueocean-personalization:1.24.6
authorize-project:1.4.0
pam-auth:1.6
jdk-tool:1.5
blueocean-i18n:1.24.6
blueocean-jwt:1.24.6
bouncycastle-api:2.20
gitlab-api:1.0.6
ldapemail:0.8
maven-plugin:3.10
javadoc:1.6
github-api:1.123
pipeline-rest-api:2.19
okhttp-api:3.14.9
job-dsl:1.77
workflow-multibranch:2.23
snakeyaml-api:1.27.0
cloudbees-folder:6.15
extensible-choice-parameter:1.7.0
http_request:1.9.0
blueocean-rest:1.24.6
mailer:1.34
workflow-basic-steps:2.23
lockable-resources:2.10
conditional-buildstep:1.4.1
pipeline-graph-analysis:1.10
metrics:4.0.2.7
git-server:1.9
plugin-util-api:2.1.0
workflow-job:2.40
code-coverage-api:1.3.2
docker-workflow:1.26
workflow-aggregator:2.6
ssh-steps:2.0.0
authentication-tokens:1.4
active-directory:2.23
ssh-credentials:1.18.1
command-launcher:1.5
PrioritySorter:4.0.0
scm-api:2.6.4
git-client:3.7.1
rebuild:1.32
sonar:2.13.1
artifactory:3.10.6
workflow-durable-task-step:2.38
xvfb:1.1.3
config-file-provider:3.8.0
blueocean-github-pipeline:1.24.6
blueocean-pipeline-api-impl:1.24.6
dependency-check-jenkins-plugin:5.1.1
pipeline-input-step:2.12
warnings-ng:9.0.1
blueocean-git-pipeline:1.24.6
jacoco:3.1.1
ace-editor:1.1
workflow-api:2.42
slack:2.47
ant:1.11
gradle:1.36
plain-credentials:1.7
antisamy-markup-formatter:2.1
htmlpublisher:1.25
font-awesome-api:5.15.2-2
workflow-step-api:2.23
credentials-binding:1.24
blueocean-events:1.24.6
workflow-cps:2.90
sse-gateway:1.24
parameterized-trigger:2.40
blueocean-dashboard:1.24.6
workflow-scm-step:2.12
build-failure-analyzer:2.0.0
token-macro:2.15
show-build-parameters:1.0
display-url-api:2.3.4
jenkins-design-language:1.24.6
pipeline-stage-tags-metadata:1.8.4
blueocean-bitbucket-pipeline:1.24.6
ssh-slaves:1.31.5
external-monitor-job:1.7
docker-java-api:3.1.5.2
monitoring:1.87.0
ivytrigger:0.35
blueocean:1.24.6
echarts-api:5.1.0-2
analysis-model-api:10.0.0
copy-project-link:1.5
git:4.7.1
blueocean-pipeline-editor:1.24.6
windows-slaves:1.7
pipeline-build-step:2.13
popper-api:1.16.1-2
pipeline-milestone-step:1.3.2
pipeline-model-extensions:1.8.4
jjwt-api:0.11.2-9.c8b45b8bb173
bootstrap4-api:4.6.0-3
handy-uri-templates-2-api:2.1.8-1.0
durable-task:1.35
github-branch-source:2.10.2
structs:1.22
blueocean-display-url:2.4.1
ivy:2.1
pipeline-model-api:1.8.4
ssh-agent:1.22
powershell:1.4
favorite:2.3.3
docker-plugin:1.2.2
blueocean-core-js:1.24.6
email-ext:2.82
cloudbees-bitbucket-branch-source:2.9.8
workflow-support:3.8
```

### Reproduction steps

- Start Jenkins Docker Instance
- Start GitLab self-managed instance
- connect both
- create a group in gitlab
- create a organization folder in Jenkins for the group
- copy URL of icon

### Results

Expected result:

https://ci.example.com/path-to-the-icon

Actual result:

http://ci.example.com/path-to-the-icon

Seems to ignore the HTTP protocol given in the configured URL.