[bugfix] Explicitly propagate filter results from statuses to their boosts in API responses

[VyrCossont]

Description

Explicitly propagate .Filtered from an original status to its boosts in the type converter, the same way we explicitly propagate ErrHideStatus.

This changes one line of actual code. The tests either ensure that existing filter-matching behavior continues (see #3128) or that .Filtered is copied.

Checklist

• I/we have read the GoToSocial contribution guidelines.
• I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
• I/we have not leveraged AI to create the proposed changes.
• I/we have performed a self-review of added code.
• I/we have written code that is legible and maintainable by others.
• I/we have commented the added code, particularly in hard-to-understand areas.
• I/we have made any necessary changes to documentation.
• I/we have added tests that cover new code.
• I/we have run tests and they pass locally with the changes.
• I/we have run go fmt ./... and golangci-lint run.