Widget summary fails if setting name overlap with another paragraph widgets

Problem/Motivation

ParagraphsWidget introduces getSettingOptions method to retrieve list of available options. If another widget uses the same settings_name as ParagraphsWidget, ie. edit_mode, closed_mode, autocollapse or add_mode, but provides custom list of options switching back to Paragraphs EXPERIMENTAL widget will cause AjaxError, because selected option could not be found in the array returned by getSettingOptions.

Here's the problematic code fragment:

    $edit_mode = $this->getSettingOptions('edit_mode')[$this->getSetting('edit_mode')];
    $closed_mode = $this->getSettingOptions('closed_mode')[$this->getSetting('closed_mode')];
    $add_mode = $this->getSettingOptions('add_mode')[$this->getSetting('add_mode')];

Ex. if $this->getSetting('add_mode') returns radios, because it was a valid option for previously selected widget, the code above will fail with Undefined offset error.

Proposed resolution

Add method to retrieve option label and fallback to key if the label cannot be found.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet