Emoji missing from font error

cause unknown:

```bash
tex-bot-py-v2 | 2025-08-28T17:43:41.483049089Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 128172 (\N{SPEECH BALLOON}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.483114722Z matplotlib.pyplot.savefig(plot_file, format="png")
tex-bot-py-v2 | 2025-08-28T17:43:41.483605033Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 127836 (\N{STEAMING BOWL}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.483624169Z matplotlib.pyplot.savefig(plot_file, format="png")
tex-bot-py-v2 | 2025-08-28T17:43:41.484020572Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 128054 (\N{DOG FACE}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.484043745Z matplotlib.pyplot.savefig(plot_file, format="png")
tex-bot-py-v2 | 2025-08-28T17:43:41.484441542Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 127969 (\N{HOUSE WITH GARDEN}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.484453314Z matplotlib.pyplot.savefig(plot_file, format="png")
tex-bot-py-v2 | 2025-08-28T17:43:41.484921551Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 128188 (\N{BRIEFCASE}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.484943372Z matplotlib.pyplot.savefig(plot_file, format="png")
tex-bot-py-v2 | 2025-08-28T17:43:41.485282268Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 127918 (\N{VIDEO GAME}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.485294201Z matplotlib.pyplot.savefig(plot_file, format="png")
tex-bot-py-v2 | 2025-08-28T17:43:41.485802324Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 127760 (\N{GLOBE WITH MERIDIANS}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.485842770Z matplotlib.pyplot.savefig(plot_file, format="png")
tex-bot-py-v2 | 2025-08-28T17:43:41.486098078Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 128250 (\N{TELEVISION}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.486110542Z matplotlib.pyplot.savefig(plot_file, format="png")
tex-bot-py-v2 | 2025-08-28T17:43:41.486472431Z /app/cogs/stats/graphs.py:115: UserWarning: Glyph 9917 (\N{SOCCER BALL}) missing from font(s) DejaVu Sans.
tex-bot-py-v2 | 2025-08-28T17:43:41.486505483Z matplotlib.pyplot.savefig(plot_file, format="png")```

Beginne bei cogs/stats/graphs.py in Zeile 115 und reproduziere die Warnung beim Erzeugen der PNG-Datei. Verfolge, wie die aufgeführten Emoji-Bezeichnungen matplotlib.pyplot.savefig erreichen. Als erledigt gilt die Aufgabe, wenn die erzeugten Diagramme diese Emoji ohne die gemeldeten missing-glyph warnings verarbeiten.

Vom Indexierungsmodell aus dem Issue-Text verfasst.