Description of the problem

Hello!! Currently, mne.reports.add_figure() is broken when passing svg to image_format.

Steps to reproduce

import mne
import matplotlib.pyplot as plt
report = mne.Report(title='SVG Image Format Test')
fig, _ = plt.subplots()
report.add_figure(fig=fig, title='Attempting SVG Add', image_format='svg')
report.save('svg_test_report.html', overwrite=True)

Link to data

No response

Expected results

I expected the html report to show a plot of some sort. Instead it shows text.

Actual results

Additional information

mne.sys_info()
Platform Linux-5.19.0-38-generic-x86_64-with-glibc2.35
Python 3.10.10 | packaged by conda-forge | (main, Mar 24 2023, 20:08:06) [GCC 11.3.0]
Executable /home/erica/miniconda3/envs/dev_2023/bin/python
CPU x86_64 (24 cores)
Memory 62.7 GB

Core
├☑ mne 1.4.0.dev105+g686857c55
├☑ numpy 1.23.5 (OpenBLAS 0.3.21 with 12 threads)
├☑ scipy 1.10.1
├☑ matplotlib 3.7.1 (backend=QtAgg)
├☑ pooch 1.7.0
└☑ jinja2 3.1.2

Numerical (optional)
├☑ sklearn 1.2.2
├☑ numba 0.56.4
├☑ nibabel 5.0.1
├☑ nilearn 0.10.0
├☑ dipy 1.6.0
├☑ openmeeg 2.5.5
├☑ pandas 1.5.3
└☐ unavailable cupy

Visualization (optional)
├☑ pyvista 0.38.5 (OpenGL 4.6 (Core Profile) Mesa 22.2.5 via AMD Radeon RX 570 Series (polaris10, LLVM 15.0.6, DRM 3.47, 5.19.0-38-generic))
├☑ pyvistaqt 0.9.1
├☑ ipyvtklink 0.2.2
├☑ vtk 9.2.6
├☑ qtpy 2.3.1 (PyQt5=5.15.6)
├☑ pyqtgraph 0.13.2
├☑ mne-qt-browser 0.4.0
└☐ unavailable ipympl

Ecosystem (optional)
├☑ mne-bids 0.13.dev0
├☑ mne-connectivity 0.6.0dev0
└☐ unavailable mne-nirs, mne-features, mne-icalabel, mne-bids-pipeline