Seeing "No Characteristics" when creating variant in Experience Manager

After upgrading to latest release 14.7.3, the Characteristic modal stopped working in Experience Manager when trying to add a new variant for a component on an xpage.

Steps to Reproduce

1. Install brXM v14.7.3 and the Relevance Module.
2. Create a new page and place a component on the page.
3. Create a variant of the component and try to add a Characteristic.
4. See the Characteristics Modal with the message "No Characteristics"

In browser console there is this error message

ERROR Error: Uncaught (in promise): Error: Characteristic with id "city" is not supported

Which points to this function:

  _getCharacteristicConfigKey(id) {
    const customCharacteristic = Object.entries(this._characteristicsConfig)
      .find(([, value]) => value.characteristic === id);

    if (customCharacteristic) {
      return customCharacteristic[0];
    }

    // Error thrown here...
    throw new Error(`Characteristic with id "${id}" is not supported`); 
  }