highlight vulnerable to cleartext transmission of sensitive information

Highlight is an open source, full-stack monitoring platform. Highlight may record passwords on customer deployments when a password html input is switched to `type="text"` via a javascript "Show Password" button. This differs from the expected behavior which always obfuscates `type="password"` inputs. A customer may assume that switching to `type="text"` would also not record this input; hence, they would not add additional `highlight-mask` css-class obfuscation to this part of the DOM, resulting in unintentional recording of a password value when a `Show Password` button is used. This issue was patched in version 6.0.0. This patch tracks changes to the `type` attribute of an input to ensure an input that used to be a `type="password"` continues to be obfuscated.