Filter flags in dashboard based on flag state

[dabeeeenster]

It would be useful to be able to filter flags based on both their boolean and text values. Suggest adding another dropdown here titled "State" which opens a drop down to allow this:

[dabeeeenster]

Yes that would be great thanks!

[matthewelwell]

Re-opening for 2 reasons:

1. The flag on the FE hasn't been enabled yet
2. There seems to be scenarios where it doesn't work correctly, e.g. see the 'Demo' environment in the 'Flagsmith Website'. Screenshot below.

Given that these are 2 features that we use heavily in demos, I imagine it could be something versioning related since we often demo change requests using these features.

[matthewelwell]

@zachaysan looking into this, I believe it's because we're using FeatureState.get_live_feature_states() which actually (and perhaps confusingly) returns all feature states which are considered 'live' to the engine, but doesn't (as we expected it to) only return the latest live version. We should (I believe) change features/views.py#L235-L238 to use features.versioning.versioning_service.get_environment_flags_list instead.