Audit and validate event rejection checks that may no longer be necessary

[coderabbitai]

Context

Following the refactor in #252, specifically the discussion at #252 (comment), we need to audit all places where events are checked for rejection and errors are rethrown.

Task

Check and validate all places in the codebase where:

• An event is checked using .rejected property
• An error is thrown based on .rejectReason or .rejectedReason

According to @debdutdeb, these checks should no longer be necessary after the state calculation refactor.

Location Examples

• packages/federation-sdk/src/services/room.service.ts line ~929-933
• Search for patterns like if (.*event.*\.rejected) across the codebase

Expected Outcome

Either:

• Remove unnecessary rejection checks if they're redundant
• Document why certain checks are still needed
• Ensure proper error handling is in place where rejection checks are removed

Related

• PR: refactor: state calculation #252
• Comment: refactor: state calculation #252 (comment)
• Requested by: @debdutdeb