Consistently remove boolean attributes for falsy values

Editor assessment

fix(runtime-dom) states that boolean attributes are now consistently removed for falsy values, which names the corrected behavior and area precisely. The fix type and scope fit, the header is imperative and unterminated and carries the pull request, and no footer is needed. No body explains the prior inconsistency, but the subject is specific and self-contained. Clear and correctly classified, it is publishable with only a small context gap.