fix(iswf): Surfaces linked issues for Sentry Apps with no UI components

[GabeVillalobos]

Shows linked Sentry App issues, even if now UI components for Link or Create are defined. As before, these linked issues will only be visible for Sentry Apps that are installed. Unlinking functionality will still work the same as before.

Some notable caveats:

1. This will not show the Sentry App icon due to the missing components
2. As mentioned before, this will not include linked issues for uninstalled Sentry Apps
3. Installation lookup uses the service_type field on the PlatformExternalIssue model, which can be a little funky if a Sentry App slug is changed, meaning issues can disappear if this occurs

Resolves #108103

[sentry]

Bug: If a Sentry App's slug is changed, previously linked external issues for that app will no longer be displayed because the lookup relies on the original slug.
_{Severity: LOW}

Suggested Fix

To ensure a stable association, use an immutable identifier for the Sentry App, such as its ID, for the lookup instead of the mutable slug. This would prevent the connection from breaking if the slug is ever modified.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location:
static/app/components/group/externalIssuesList/hooks/useSentryAppExternalIssues.tsx#L116-L118

Potential issue: The `PlatformExternalIssue.service_type` field is set to the Sentry
App's slug at the time an external issue is created. The frontend code later matches
this stored `service_type` against the current slug of installed Sentry Apps. If a
Sentry App's slug is changed after issues have been linked, the comparison will fail.
This causes previously linked external issues to silently disappear from the UI, as they
can no longer be associated with the correct Sentry App installation.

_{Did we get this right? 👍 / 👎 to inform future reviews.}

[GabeVillalobos]

Already called this out in the description. While true, displaying all issues, including those for uninstalled sentry apps seems incorrect.