Add empty state when no serving platform is enabled

[DaoDaoNoCode]

Closes #1994
Closes #1995

Description

There are several checks in this PR:

When the platforms are installed:
When we enter an unlabelled project and both disableKServe and disableModelMesh feature flags are set to true, you will get the empty state to tell you to ask for the administrator to enable platform selection.

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When either platform is not installed:

On the cluster settings page:

1. You will see the grey out checkbox which prevents you from enabling it if the platform is not installed on the cluster
2. If you are the cluster admin, you will see the link to bring you to the DataScienceCluster resource page on the OpenShift console

3. If you don't have edit access to DataScienceCluster, the link button will be a plain text

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On project details page:

If the project is labeled already but the serving platform in not installed at all, you will see a loading error

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When both platforms are not installed:

You will see an error page on the global model serving page:

Of course, the cluster settings page grey both of them out because we only hide this section when you fully disable model serving.

How Has This Been Tested?

There are several parts of this:
First part:

1. You need to make sure you get both model serving platforms installed on the cluster
2. Go to the cluster settings or dashboard config, disable both of the available platforms
3. Wait for 2 mins
4. Create a new project and go to the model serving section, you will see the empty state as is shown above in the description
5. The labeled projects should still be able to see the model/model server list

Second part:

1. Now you can try to remove one of the serving platforms by changing the component from Managed to Removed, making sure the status changed to false, which means that platform is not available anymore
2. Go to the cluster settings page, make sure the corresponding checkbox is greyed out
3. Click on the help icon on the description, make sure you could see the text and access the link the the DataScienceCluster resource
4. Try to impersonate a dashboard admin but not cluster admin user, you should only be able to see the plain text in the popover, but not the link
5. Try to go to a project you created before, it's better to be a project with the serving platform labeled already and you removed the platform, you should see a loading error

Third part:

1. Now you can removed the other serving platform, now none of the serving platform is available
2. Go to the global model serving page, you should error an error state and cannot see any deployed model now

Test Impact

Update some feature flag related tests, and add an integration test to test the empty state.

Request review criteria:

Self checklist (all need to be checked):

• The developer has manually tested the changes and verified that the changes work
• Commits have been squashed into descriptive, self-contained units of work (e.g. 'WIP' and 'Implements feedback' style messages have been removed)
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has added tests or explained why testing cannot be added (unit tests & storybook for related changes)

If you have UI changes:

• Included any necessary screenshots or gifs if it was a UI change.
• Included tags to the UX team if it was a UI/UX change (find relevant UX in the SMEs section).

After the PR is posted & before it merges:

• The developer has tested their solution on a cluster by using the image produced by the PR to main

[DaoDaoNoCode]

@vconzola Could you check the screenshot in the description?

[vconzola]

@DaoDaoNoCode LGTM.

[DaoDaoNoCode]

@vconzola @kaedward I updated the descriptions and the screenshots based on the discussion this afternoon, could you check it again?

[lucferbux]

/lgtm

Tested an it's working, we can do a rundown next week with UX to spot mismatches but is high priority to integrate all the code today.

[openshift-ci]

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