feat(compass-web): add onFailToLoadConnections callback COMPASS-8657

[mabaasit]

With this prop, we will be able to handle showing custom error page instead of a toast on mms side.

Description

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added
• I have signed the MongoDB Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Open Questions

Dependents

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)

[paula-stacho]

The description says "instead of a toast", but I don't see removing the old toast - did we have no error handling before?

[mabaasit]

we have no error handling before

We did have error handling before, but we did not show any toast (because we never fail to load compass connections). So i added that, to show the toast for CompassDesktop). And for CompassWeb, will let mms handle it.

[paula-stacho]

I'd suggest adding a test or two, but otherwise looks good!