[UI] Handle Segment Union Types Properly

[nicholas-codecov]

Currently we do not handle the segment union type properly in Gazebo, we only handle the happy path. What happens instead, is that the user sees an entire error page which is not ideal.

The ideal outcome is that we update the GQL queries that call segments field and handle all of the different types, see the screenshot below.

After updating the queries we'll also need to update the zod schemas with a discriminated union type on the __typename field, similar to that of Repository.

Once those two things are done, we'll have to update the respective file diffs to display a custom error messages in these cases.

segments union type:

[suejung-sentry]

Here's some more info on the probable cause / how to reproduce - #2811

[eliatcodecov]

Assigning to @katia-sentry such that this can be assigned along with #2811 when that is handed off to an engineer.