Demo does not compile with Vaadin 23.3.0

[javier-godoy]

ERROR in frontend/generated/jar-resources/fc-font-awesome-gallery.ts:10:3
TS2564: Property 'family' has no initializer and is not definitely assigned in the constructor.
     8 |
     9 |   @property()
  > 10 |   family:  string;
       |   ^^^^^^
    11 |
    12 |   @property()
    13 |   caption: string;

ERROR in frontend/generated/jar-resources/fc-font-awesome-gallery.ts:13:3
TS2564: Property 'caption' has no initializer and is not definitely assigned in the constructor.
    11 |
    12 |   @property()
  > 13 |   caption: string;
       |   ^^^^^^^
    14 |
    15 |   @property()
    16 |   filterString: string;

ERROR in frontend/generated/jar-resources/fc-font-awesome-gallery.ts:16:3
TS2564: Property 'filterString' has no initializer and is not definitely assigned in the constructor.
    14 |
    15 |   @property()
  > 16 |   filterString: string;
       |   ^^^^^^^^^^^^
    17 |
    18 |   @property()
    19 |   _icons: string[];

ERROR in frontend/generated/jar-resources/fc-font-awesome-gallery.ts:19:3
TS2564: Property '_icons' has no initializer and is not definitely assigned in the constructor.
    17 |
    18 |   @property()
  > 19 |   _icons: string[];
       |   ^^^^^^
    20 |
    21 |   static styles = css`
    22 |     :host([empty]) {

ERROR in frontend/generated/jar-resources/fc-font-awesome-gallery.ts:67:13

    65 |     if (changedProps.has('family')) {
    66 |         const iconset = document.querySelector("fc-iconset[name='"+this.family+"']") as any;
  > 67 |         let icons = [];
       |             ^^^^^
    68 |         if (iconset) {
    69 |             (iconset as any).applyIcon(null);
    70 |             icons = Object.keys(iconset._icons).concat(Object.keys(iconset._alias)).sort();

ERROR in frontend/generated/jar-resources/fc-font-awesome-gallery.ts:72:23
TS7005: Variable 'icons' implicitly has an 'any[]' type.
    70 |             icons = Object.keys(iconset._icons).concat(Object.keys(iconset._alias)).sort();
    71 |         }
  > 72 |         this._icons = icons;
       |                       ^^^^^
    73 |     }
    74 |
    75 |     let hasVisibleIcons = !!this!.shadowRoot.querySelector(".icon:not([hidden])");

ERROR in frontend/generated/jar-resources/fc-font-awesome-gallery.ts:75:29
TS2531: Object is possibly 'null'.
    73 |     }
    74 |
  > 75 |     let hasVisibleIcons = !!this!.shadowRoot.querySelector(".icon:not([hidden])");
       |                             ^^^^^^^^^^^^^^^^
    76 |     this.toggleAttribute('empty', !hasVisibleIcons);
    77 |
)");

ERROR in frontend/generated/jar-resources/fc-font-awesome-gallery.ts:79:5
TS2531: Object is possibly 'null'.
    77 |
)");
  > 79 |     document.querySelector('.no-results').toggleAttribute('hidden', globalHasVisibleIcons);
       |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    80 |   }
    81 |
    82 |   createButton(icon: String) {