fix(api): Do not return deleted web experiments for `/api/projects/:project_id/web_experiments/`

[lshaowei18]

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Problem

Closes #33670

Changes

I believe the router for api is using WebExperimentViewSet, and as referenced from the other view sets it seems like most are using safely_get_queryset if they want to filter/exclude.

Did you write or update any docs for this change?

• [x] No docs needed for this change

How did you test this code?

Locally:

1. Create no code experiment
2. Delete it
3. Fire off get api request should not return me the experiment.

P.S: Is there any unit test that I need to write for this?