Wrong background colour using latest version

[DiegoF90]

The latest version of voila==0.5.6 (jupyter-client==8.6.2, jupyter-server==2.14.0) and ipysheet==0.7.0 seem to ignore the theme of the notebook.

For example if I select the theme to be dark, the background of the table is white (although the text is indeed using the theme and becomes white, hence unreadable).

This wasn't an issue e.g. with voila=0.4.0, jupyter_client==7.4.1, jupyter-server==1.24.0. Using these versions the table correctly uses a black background.

Please see below a minimal reproducible example:

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "afc59352-a11c-484e-a5d3-601e05ad7d37",
   "metadata": {
    "editable": true,
    "slideshow": {
     "slide_type": ""
    },
    "tags": []
   },
   "outputs": [],
   "source": [
    "import ipysheet\n",
    "sheet = ipysheet.sheet(columns=2, rows=3, column_headers=[\"A\", \"B\"])\n",
    "ipysheet.column(0, [1, 2, 3])\n",
    "ipysheet.column(1, [4, 5, 6])\n",
    "display(sheet)"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3 (ipykernel)",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.11.7"
  },
  "voila": {
   "theme": "dark"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 5
}