Many `parseInt` call-sites already provide the `radix` argument, and this rule helps improve consistency in the code-base; see https://eslint.org/docs/latest/rules/radix
*Please note:* The rule is disabled in `src/scripting_api/util.js` for now, since it's not obvious at a glance (at least to me) what the correct `radix` argument should be there.
- Point the `addSignatureDescription` respectively `editSignatureDescription` labels to their actual `input`-elements (this way clicking the label will actually focus the input).
- Add the event listener to the `addSignatureDescription`-input, rather than its `span`-element (this is consistent with the `editSignatureDescription` case).
- Correctly check if the `addSignatureDescription`-input is empty, since we're accidentally comparing with its `span`-element.
- Remove unbalanced, and likely accidentally added, `</span>` tags.
It's now pretty common that we only want to close a `dialog` *if* it's currently active, to avoid throwing errors, and this new method provides a shorter and more convenient way to achieve that.
