chore: feature flag resiliency

[EDsCODE]

What does this PR do?

• resiliency points for https://github.com/PostHog/posthog/issues/13627

Where should the reviewer start?

How should this be manually tested?

Any background context you want to provide?

What are the relevant tickets?

Screenshots or screencasts (if UI/UX change)

Questions:

• Does the docs need an update?
• Are there any security concerns?
• Do we need to update engineering / success?

[liyiy]

should we add tests for this? (asking for android too)

[EDsCODE]

Good point, the no-replacement on error yes I would say so. For timeouts idts