Removing Amplitude integration causes any subsequent additions to fail

[dannydtk]

Describe the bug

The first time you add Amplitude integration for a particular Flagsmith environment it's added successfully. If you try to remove it and add it again by clicking Save nothing happens and the underlying request POST https://api.flagsmith.com/api/v1/environments/<env_id>/integrations/amplitude/ fails with 500 Server error.

If you use a fresh environment it works until you try to remove and re-add the integration.

To Reproduce

Steps to reproduce the behavior:

1. Go to https://app.flagsmith.com/project/<project_id>/integrations (Integrations tab)
2. Add Amplitude integration
3. Select environment A
4. Provide valid Amplitude API key
5. Click on Save
6. Remove the integration you've just added by clicking the red trash bin icon next to it
7. Repeat points 3-5 for the same A environment (re-add the integration)
8. Observe how the Save button is getting disabled and nothing happens. You can see in the network tab POST https://api.flagsmith.com/api/v1/environments/<env_id>/integrations/amplitude/ failing with 500 Server error.

Expected behavior

You can successfully re-add Amplitude integration for the same Flagsmith environment.

How are you running Flagsmith?

• Self Hosted with Docker
• Self Hosted with Kubernetes
• SaaS at flagsmith.com
• Some other way

[dabeeeenster]

Related: Sentry Issue: FLAGSMITH-API-37S
and closed related PR which was merged #2217

[dannydtk]

Looks like it was fixed in v2.54.0 but we're still experiencing the issue using the latest v2.63.2 SaaS.

[dannydtk]

I can also see the changes to serializers from #2217 omitted Amplitude integration.

flagsmith/api/integrations/amplitude/serializers.py

Line 6 in da2b4a7

class AmplitudeConfigurationSerializer(serializers.ModelSerializer):