WD-8309 - feat: Display error when trying to retrieve models info

[vladimir-cucu]

Done

• Throw the “Unable to fetch the status.” error instead of using return. Afterward, throw the error, so that it is further caught in fetchAllModelStatuses().
• If less than 10% of models error out, no error is processed in fetchAllModelStatuses(). Else, throw the error back, so that it is further caught in modelPollerMiddleware().
• When trying to retrieve models info in modelPollerMiddleware(), send "Unable to load models." error if it is the first polling and all models error out, "Unable to load some models." error if it is the first polling and some models error out, "Unable to load latest model data." if it is later polling and the error appears in fetchAllModelStatuses() call, else send "Unable to list or update models." error. The error should be sent to juju -> modelsErrors in Redux store.
• Display the previously mentioned error inline in pages/ModelsIndex/ModelsIndex.tsx.

QA

• Modify the code of modelPollerMiddleware() to throw an error on line 217.
• Verify that the error gets displayed on Models page and logged into the console.

Details

• https://warthogs.atlassian.net/browse/WD-8309

Screenshots

[webteam-app]

Demo starting at https://juju-dashboard-1686.demos.haus

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (5e8ef26) 0.00% compared to head (2a43750) 95.02%. Report is 4 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1686 +/- ## ========================================= + Coverage 0 95.02% +95.02% ========================================= Files 0 178 +178 Lines 0 5207 +5207 Branches 0 1524 +1524 ========================================= + Hits 0 4948 +4948 - Misses 0 239 +239 - Partials 0 20 +20 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.