MGMT-15330: Make the custom manifest YAML editor read-only

[jgyselov]

https://issues.redhat.com/browse/MGMT-15330

[openshift-ci-robot]

@jgyselov: This pull request references MGMT-15330 which is a valid jira issue.

In response to [this](https://github.com/openshift-assisted/assisted-installer-ui/pull/2273): >https://issues.redhat.com/browse/MGMT-15330 Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[ammont82]

@jgyselov these changes don't affect tests for yaml's upload?

[jgyselov]

@jgyselov these changes don't affect tests for yaml's upload?

If it did, the test wouldn't pass without changes. (We are using the upload function in the tests, we are not typing the YAMLs manually.)

[ammont82]

@jgyselov these changes don't affect tests for yaml's upload?

If it did, the test wouldn't pass without changes. (We are using the upload function in the tests, we are not typing the YAMLs manually.)

Perfect. Sorry, I wrote my comment before all tests passed. Good job

[jgyselov]

Perfect. Sorry, I wrote my comment before all tests passed.

I usually run the tests locally before I push to GH. So in case they fail, I can properly look into it right away. :slightly_smiling_face:

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: ammont82, jgyselov, jkilzi

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files: - **[OWNERS](https://github.com/openshift-assisted/assisted-installer-ui/blob/master/OWNERS)** Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[jkilzi]

@talhil-rh FYI