Block upgrading partner chart to a feature chart repo

[anupama2501]

Setup

Rancher version: 2.6-head 56f0c2d
Browser type & version: Chrome

Describe the bug
When we install an app from a partner chart repo, we can upgrade the same chart via feature charts if the chart also exists in the feature charts default repo.

To Reproduce

1. Create a cluster 3 worker, 1 etcd, 1cp [required spec as I tested with istio app]
2. From the cluster's apps & market >> Repositories >> create a repo [ I forked feature charts to my repositories. If needed can make use of this https://github.com/anupama2501/charts ]
3. Select the option Git repository containing Helm chart or cluster template definitions, Git repo URL :https://github.com/anupama2501/charts and branch:dev-v2.6 , name:test
4. Once the repo is active, navigate to charts and from the chart repos drop down select test
5. Install monitoring any version and install istio version 1.9.6
6. Once the app is installed, from the charts page select Rancher repo from the drop down
7. Navigate to istio chart and select the version 100.2.0+up1.12.6 which is not present in the test repo versions of istio.

Result
Chart upgrades successfully and partner chart is upgraded to feature chart

Expected Result
Disallowing the upgrade of partner charts to feature charts

[gaktive]

As a note to docs, the release note label here is if we can't get this in for 2.6.5.

[gaktive]

Need to push to 2.6.6. Still need to document this for 2.6.5.

[gaktive]

One option: we could provide a warning if an admin tries to do this. The balancing act is that this behaviour is something helm allows you to do but we have to consider protecting users from doing this in Rancher.